Closed-loop color control technology during printing (2)

The closed loop color control system itself is mounted on the printing press compared to the open system method. The detection device used, such as a densitometer, colorimeter or CCD camera, is usually installed behind the cooling roller to scan the color patches on the printed sheet. , And compare with the preset target density value to get the ink density deviation. Once a reading outside the tolerance range is obtained, the system automatically emits an adjustment signal and automatically adjusts itself as soon as the machine is running. In contrast, when making any settings in an open system, it is necessary to take out the printed sheets, make off-line measurements with a densitometer or other instrument, and then make adjustments to the ink keys. Its efficiency and results are self-evident. From this point of view, real-time closed-loop control has been implemented on rotary presses. Similarly, we can see that the biggest advantage of closed-loop color control is real-time (first time) measurement and adjustment of the ink to ensure the stability of the color. This also greatly shortens the preparatory work time before printing, and replaces human judgments and manual adjustments with scientific electronic and digital information.

Advantages of closed-loop color control

Although the closed-loop color control system is not cheap, such as installing a set of about $200,000 on a rotary press, some experts believe that its value far exceeds its price. The advantages of a closed-loop color control system include:

Make the printing quality more stable;

Reduce artificial changes caused by different skilled workers;

Reduce waste and time before printing (test printing);

Improve customer satisfaction;

Reduce paper and ink consumption

Improve the efficiency of ink-ink balance adjustment;

Industrial standards such as SWOP can be used in the printing process.

Obviously, the use of a closed-loop color control system not only greatly improves the production efficiency and reduces the waste of materials such as paper and ink. It is undoubtedly a huge “liberation” for printing workers. The benefits of closed-loop systems for the job.

Solve the problem of "eye fatigue"

In general, after 8 to 12 hours of work, the printer operator's sensitivity to color changes will be reduced, and continuous work will inevitably cause eye fatigue, leading to errors in color judgment. Now the machine can take on this task, and the human eye's fatigue problem is naturally solved.

Operators can handle problems other than color

Closed-loop systems warn the operator when the variable exceeds an acceptable range. The operator knows that the system maintains a balance of colors in “dueing its responsibilities”, so they can “free up hands” to check the balance of ink and water, and can focus on folding, tension, and other issues to greatly increase production efficiency.

One person operation management

Labor savings are a major advantage of closed-loop control over offline systems. Web printers can provide customers with a range of density changes throughout the printing process, indicating a new level of professionalism. This useful document is also valuable when customers have doubts about print quality. Due to the reduction in the number of color adjustments and the color adjustment operation, the number of offline scans is reduced. A double web press can manage color and registration by an operator.

Exclude subjectivity

We know that no two printers look at the color in the same way, but the closed-loop color control system is compared with the preset target density to ensure the adjustment of the ink spoon and the stability of the color quality, excluding human subjectivity. .

Reduce setting differences

Different operator levels and different ways of adjustment can result in different adjustment settings during the printing process. What will the situation be like after two shifts? A large number of studies have shown that differences between printers can increase the variability of production. The use of a closed-loop control system eliminates the problem of people and color "games."

(to be continued)