Solution to several problems in packaging and printing

Several problems that affect the quality of water-based ink and should pay attention

1. Since the ink is a pure water system, do not mix the ink with alcoholic inks and solvent-based inks or add organic solvents to the inks to avoid print quality problems.

2. Ink should be present indoors at room temperature between 5°C and 50°C.

3. When using, stir the ink in the bucket with a stirring rod, measure the viscosity and pour it into the ink tank. If the viscosity is too high or too low, you can add thinner or thickener to adjust.

4. During the printing process, due to the volatilization of water, the viscosity of the ink will increase and the PH value will drop. The PH value should be controlled between 8.5 and 9.5. If it exceeds this range, PH stabilizer can be used to adjust the viscosity and The pH is stable.

5. Under normal circumstances, the ink is very suitable for high-speed printing. If the drying speed is too fast or the printing effect is not good during low-speed printing, a certain proportion of slow-drying agent may be added.

6. After the printing is completed, the remaining ink should be collected back into the corresponding original bucket or the lid of the ink tank should be tightly closed for the next use. Be careful not to make the ink surface conjunctiva, thicken or even dry due to the volatilization of water.

7. The ink remaining on the printing setup after printing can be washed with fresh water before it is completely dried, and the ink that cannot be washed with fresh water can be cleaned with a cleaning agent.

Use of ink additives

The printability of ink is influenced by the printing conditions, the surface characteristics of the substrate, the ambient temperature and humidity, and the length of time the ink is stored. Therefore, when using ink, some additives are required to make fine adjustments to the ink to obtain the best printing. effect.

1. Color: used to darken color. The amount is less than 30%, more than 30% will make the content of the binder in the ink too low, resulting in decreased adhesion and wear resistance.

2. Diluent: used to reduce the depth of color, the amount is not good. Adding a large amount of diluting agent may cause the ink viscosity to slightly increase, and at this time, a small amount of diluent may be added at the same time to adjust.

3. Thinner: used to reduce the viscosity of the ink. The dosage of less than 3% will not reduce the color depth of the ink and keep the PH value of the ink constant. Adding more diluent or diluting with tap water with high hardness will lead to the generation of bubbles, and can also be added at the same time to eliminate the foaming agent. bubble. The thinner should be added slowly while stirring to prevent the viscosity from being too low.

4. Slow drying agent: used to reduce the drying speed of ink, the amount is less than 10%.

5. Fast drying agent: used to accelerate the drying speed of ink, the amount is less than 3%.

6. Defoamer: used to eliminate air bubbles, the dosage is 1‰2‰.

7. PH stabilizer: used to maintain the PH value of the ink, the amount to maintain the PH value of the ink is preferably 8.5-9.5.

8. Thickener: used to increase the viscosity of ink, the amount of 0.5% -1%.

How to solve printing double shadow

The edges of printing strokes are anti-warped, and the printing is double-shadow. This is one of the common problems in the printing production process. Here, the printer of the double-roller ink supply system is used as an example to analyze:


1. Adjustment pressure: The pressure here is divided into upper pressure and lower pressure. The upper pressure is the gap between the anilox roller and the printing wheel; the lower pressure is the gap between the printing wheel and the printing pressure roller. When the pressure is large, the gap is small, and when the pressure is low, the gap is large. Of course, the effects of over-pressing and under-pressing are different. Then when there is a problem with double shadows, how do you judge whether the pressure is too high or the pressure is too high? This requires careful observation of the printing effect. If the double shadow appears around the strokes of the handwriting, it is caused by excessive pressure. Consider Appropriately reduce the pressure, which is appropriate to enlarge the gap between the anilox roller and the printing wheel, in order to feed the direction, if the double image appears in the paper feed direction, then it is caused by excessive pressure. Considering that the down pressure is properly reduced, that is, the clearance between printing wheels is increased, the effect will be improved.


3. Layout design: In the actual production process, we often encounter the situation on the ground and the small print layout. In the printing process, if the on-site version is printed plainly and full, the pressure will be appropriately larger, but at the same time it will make small prints. Ghosting phenomenon. In addition to the above factors, there are other factors such as poor transferability of the ink itself, unevenness of the paperboard, and unequal compressive strength. When printing, to achieve a bright, full, good coverage effect, the first consideration is to adjust the parameters of the equipment, including pressure.

Although cushions can function well as cushions, the possibility of double shadowing cannot be fundamentally avoided. because

2. Checking the printing plate: There are many reasons for the double stroke of the printing plate because of the strokes of the strokes of the printing plate, but the most direct reason is fine. The surface of the writing strokes is not smooth and uneven, or the printing is caused by pressure. To achieve a satisfactory version of the poor transferability of ink and other factors in the production, all the possible printing effects require that the personnel's technology, equipment, printing Plates, cardboard, ink, and auxiliary materials be properly matched. Therefore, at present, we must fundamentally solve the problem of double-image, and we must also work together with colleagues in the carton industry.

Corrugated industrial starch and heat process control

The heat transfer rate is inversely proportional to the production speed of the corrugated board production line. Therefore, sometimes the carton plant has six times the difference in heating of the same starch paste glue on different corrugated board production lines.

When producing core paper with high absorbency or using water-resistant starch, the weight of the paperboard will be very different.

In the corrugated industry, the consumption of starch paste includes:

1. Current process limitations
2. The production speed of corrugated board production line is too wide. As a "shock absorber" in the heating process, making starch too much;

Excessive starch may cause problems including:

1. The cardboard is too soft and excessively watery;
2. Thermal stress limits the speed of production;
3. Layering of paperboard paste adhesive;
4. "Washboard" phenomenon 5. Over time, the cardboard warped.

Author / Chen Xirong

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