Reduce paper consumption in thermoset web offset printing (top)

The waste of paper in printing is unavoidable, but there are ways to minimize it. In order to meet customer requirements, Manroland has paid close attention to the possibility of a total reduction in paper waste. In other words, we must carefully examine the factors that cause paper waste. This can only be achieved with industrial partners such as desiccant manufacturers or paper and ink suppliers. The strength of these development engineers working collaboratively with colleagues in different areas and product areas has also played an important role. For example, the technical know-how of operating a sheet-fed press was used in an optimised design project by Manroland in collaboration with Eurografica-Systempl a-nungs at Imprimere Saint-Paul in Luxembourg. Here, in the newspaper printing environment, measures to reduce the paper waste rate were used very successfully. The waste at the time of starting up was reduced by 80%, and the cost saved by production and related projects was repaid many times.

At the same time, in order to tap the potential of reducing paper waste in commercial web offset printing, extensive testing has also been conducted.

In thermosetting web offset printing, paper is wasted by many different factors, so reducing waste has become a complex matter involving many variables. Only through the interaction between various measures can we achieve the goal of reducing costs by reducing paper waste.

In thermosetting web offset printing, tests focus on the conditions that may be optimized at the time of startup, acceleration, and production. Moreover, the measures taken to reduce paper waste at a certain stage are also beneficial to other phases.

Extensive testing

Only through extensive testing can we successfully achieve the effect of reducing paper waste. Through these tests, the cause of waste and the inherent wasteful factors can be systematically determined. The method of reducing paper waste developed through these test results must be tested by a large number of actual tests.

Here, the important tools are highly developed measurement and control technologies. Without these, it is virtually impossible to make progress.

This article describes methods and systems developed by Manroland to reduce paper waste, some of which were obtained in collaboration with customers and external partners.

Different expectations for quality

In the field of thermosetting web offset printing, the expectation of quality depends on the purpose of the product and there are different levels of acceptable quality. In this way, it is difficult to give a concrete description by reducing the degree of paper waste that can be achieved by the tests described below.

Reduce paper waste

As already mentioned, the following data can be roughly estimated: In the process of preparation and speedup of printing, there are generally 2,000 to 300 parts of waste, but if the method described in this paper is used, paper waste can be reduced to 1000. About. For the highest quality expectations (first-grade quality paper), 1000 wasted, newspapers achieved salesability in print color and folding registration, and the field density has reached the standard value, and the fluctuation range of the density can be minimized. Reach +/- 0.08.

These test methods have particularly positive results for those expensive and high-quality materials. Under normal circumstances, the waste of paper that is expected in printing will reach 10,000, and it will take a long time to adjust. Paper waste can be greatly improved when using the color adjustment system described in this article.

Paper waste when adjusting

In addition to special inking methods, some other accompanying methods are also very helpful in reducing paper waste. This included the use of a rapid dryer, which had a speed of 5000rph instead of 8000rph. This was done in cooperation with the dryer manufacturer Megtec. In addition, the improvement of the engine is also very helpful. The roll force system is now set at 3000rph instead of 5000rph.

Stable boot status

In order to achieve a stable start-up state, the inking device is thoroughly cleaned, and the blanket is also cleaned. This ensures that printing always has the same preset parameters.

Set a low percentage of outlets

If printing a low dot percentage, for example 10%, it takes a long time for the inking system to balance and the ink flow to a reasonable setting.

The new inking system solves this problem. Before the printing press started printing, each ink inking unit had already applied a certain amount of ink. Since the ink metering element can be preset by using the data obtained from the Production Manager Production Manager, the ink flow can be matched.

If the dot percentage is ignored, the new inking system uses only about 100 parts of waste and the printer's ink flow can reach an appropriate state.

(to be continued)