Quality Control and Control Points of Corrugated Paper Boxes for Water and Ink (Part 2)

The main points of quality control of water-based inks:

pH is a very important factor in water-based printing inks. Lack of control or incorrect pH can cause many problems and can also affect the viscosity of aqueous inks. The general water-based ink pH range should be between 8 and 9.

Control the quality of water-based inks Note the following points:

Stir before use.
Detect the ink viscosity of the printing press.
Adjust viscosity and reconfirm viscosity and pH.
The proportioning component of the water-based ink and the amount of ink transfer should be recorded in detail so that the stub can be archived and used as a reference for the printing comparison.

Water-based ink inventory management

The carton factory should reasonably guarantee the inventory of water-based inks based on the actual production conditions. To ensure a reasonable amount of color inventory, according to the finished product, semi-finished products and use, return and other items classified to establish inventory accounting records. Water-based ink storage is divided into finished ink area, semi-finished ink area, and old ink area. According to the ink's color or the relevant cartons' products to be discharged in order, only a small amount of finished ink and a proper amount of color paste will be stored, and large inventory and possible inventories will be avoided, so as to be ready for use. It is necessary to regularly carry out the inventory management of water ink in order to reasonably perform sealing, merger, etc., which can reduce the number of ink tanks and increase the storage space of ink storage rooms.

Ink management

When each machine station uses water-based ink, it must use the color number required by the production order. The first step is to see if the ink is on the spot or there is old ink that can be used for adjustment, and do the test. If you do not have the desired ink and then receive new ink, try to avoid stocking too much. The water-based ink is applied outside the barrel of the finished product water-based ink using a label.

Ink site management precautions:

When replacing the ink, the machine should be cleaned to avoid affecting the accuracy of the next print because the previous print was not washed.

In order to avoid the ink viscosity after the machine is too low, the water remaining in the machine should be discharged as much as possible.
Before going on the machine, you must carefully check whether the number of the label on the barrel is consistent with the instruction on the production order so as to avoid mistakes.

It is strictly forbidden to use the entire bucket of water-based ink on the machine, and the water-based ink is fully mixed evenly on the machine. The correct machine is the minimum amount of revolution, big drums 8 kg, large machines 10 kg. After adding new ink, the viscosity should be measured to ensure the consistency of the color before and after the production.

After starting up for a period of time, after the printing is stable, the double pair of the sample box is used. According to the situation after the color, it is judged whether ink or water is added to adjust the viscosity of the ink.

In the process of using water-based ink, do not add water, you must determine the need to add water to adjust the hue and printing effect according to the color of the sample box. If the printing process takes a long time, it is necessary to regularly add water and amine stabilizers to stabilize the printing effect (water: half hour/time; amine stabilizer O: 2 hours/time).

After the use of water-based ink, in principle, it requires the old and new ink storage, if you want to mix, must be the same number. If you accidentally fall into the wrong ink, report it to the water-based ink manager in time to avoid causing color errors the next time. Cover it with the corresponding lid to prevent dust, evaporation and crusting.

In the process of water-based ink loops, attention is paid to the generation of air bubbles. The ink pump can be opened to maintain the water-based ink loop. If foaming is severe, add appropriate amount of defoamer before preparation. Generally, the amount of defoamer is 0.1 to 0.2%.

When cleaning the printing machine and drawing new ink, try not to let the water flow into the ink tank to prevent the color from being too light due to the low viscosity. At the same time, the ink outlet of the ink return tube must be washed to avoid the unwashed ink nozzles. Put ink in the ink tank to affect the ink color.

Pay attention to the influence of ambient temperature, humidity and season on the water-based ink in the workshop, and ensure high-speed viscosity in a timely manner to ensure the printing quality.

When testing, it is necessary to adjust and record the various problems that arise, and carefully check the color of the sample box and the sample draft, and the problem cannot be brought into normal production.

In today's profitable carton industry, the cost of water-based inks has accounted for about 3 to 5% of the cost of cartons. Managing ink quality, usage, and printing quality will reduce production costs. Learning and absorbing the essence of the carton industry management and formulating printing management documents (including operation specifications, statistics, forms, and methods) that conform to the characteristics of the enterprise, and actively implementing the application, will surely create a greater profit margin for the enterprise.

Source: Long Chen Printing Technology Network