Corrugated Box Printing: Key Points Question Answer (I)

1. How to solve the problem of ink bleaching?
Improve solvent composition
Reduce the relative humidity of the environment;
Improve the mixing ratio of solvents, add butanol.

2. How to solve the problem of too thick ink? (Expressed as an anilox roller or printing plate too much ink)
Add stabilizers and other solvents to adjust;
Adjust the engagement on the roller appropriately to increase or decrease the engagement pressure;
Replace ink roller or ask manufacturer for help;
Adjust the squeegee blade to change the ink volume;
Select the appropriate anilox roller;
Use additives to reduce the ink strength.

3, how to solve the thin ink? (Expressed as lack of color intensity)
Adjust the ink roller in the right position to make more appropriate amount of ink on the roller;
Replace the anilox roller;
Clean with a suitable brush (nylon or copper brush) and a high concentration of cleaning solution;
Use a low hardness ink roller or process ink roller to rejuvenate and add new ink or color paste.

4, ink adhesion is too small how to solve? (The ink does not adhere well to the substrate)
Adjust the ink and try to change the speed of the substrate;
Inspect and correctly handle the substrate surface tension. The standard ink adhesion force is: 30×10-5--40×10-5N (30-40dyn);
The substrate must be processed before printing.

5, how to solve the ink bubble?
Reduce the circulation stirring effect;
Reduce printing speed;
Add defoamer to improve the surface tension of ink;
Add stabilizers and other solvents to reduce the viscosity of the ink.

6, how to solve the problem of print leakage?
The gap between the plate cylinder and the embossing is appropriately reduced (i.e., the plate pressure is increased), but the cardboard corrugation is prevented from being collapsed. In addition, for the large-area printing plate, the middle part of the printing plate can be properly lifted with double-sided adhesive, and the leak can also be eliminated.

7. How to solve the phenomenon of see-saw when color printing corrugated carton cover?
Cause:
In the process of laminating paper and single-faced corrugated paperboard, poor adhesion of adhesives causes excess adhesive build-up on both sides of the peaks, resulting in shrinkage of the tissues on both sides of the peak during the process of bonding and drying. Tight formation of seesaw phenomenon. Therefore, always check the amount of adhesive applied when turning on the veneer. If there is a very thin line on the paper, the glue is in the best condition and there will not be a see-saw phenomenon; if a heavy double thread occurs, the amount of glue applied will be too large, and the see-saw phenomenon will occur. The phenomenon is even more serious.
Solution:
1. The easiest and most reliable method is to change the amount of high-quality tissue, which can significantly eliminate the phenomenon of see-saw. But at the same time, it also increases the cost, so that the price of the carton is obviously increased. If the user can accept it, it can not be considered other methods.
2, increase the viscosity of corn starch adhesives. From 100ml/60s to 100ml/70-90s, to reduce the amount of sizing on the back of the peak, the seesaw phenomenon can be significantly improved with little change in cost.
3, when the use of low-volume and dry face paper, glue intake too much, it is prone to see-saw phenomenon, wetting method (cooling, humidifying, etc.) can be used to absorb a certain amount of water and then use.
4. Adjust and control the parallelism between the coating roller and the pressure roller. The clearance is moderate, generally just passing corrugated board. Strictly grasp the pressure between the pressure rollers to reduce the occurrence of jaws.
5. The most basic and effective method is to make full use of the paper's horizontal and vertical texture characteristics. The longitudinal direction of the tissue paper and the direction of the corrugated cardboard are in the shape of a "10" shape, which eliminates the phenomenon of see-saw. However, sometimes the width of the roll does not match the size of the carton, resulting in wasted paper and increased costs.

8. Flexo printing presses have the problem of ink bubbles in printing. What are the causes of such ink bubbles? How to reduce or eliminate ink bubbles?
The reason why water-based ink is easy to generate bubbles in flexo printing is because of the characteristics of water-based inks: water-based inks generally consist of insoluble pigments, water-soluble or water-dispersible resins, surfactants, water, a small amount of ethanol and other additives, and are frequently turned. It is easy to produce air bubbles.
Ways to reduce or eliminate bubbles are:
1, control the ink viscosity and PH value. The ink is prone to bubbles when it is too thick or excessively diluted. The thickening is caused by the large contact surface between the ink and the air in the ink fountain in the ink supply system, and the volatile components of the ink overflow. This causes the ink to increase year by year, and the pH value decreases. The solution is to add stabilizing agent to supplement the ammonia or amine alkaline auxiliaries evaporated in the ink, help to increase the PH value of the ink, keep the stability of the ink, and avoid the erroneous operation caused by excessive dilution of the ink due to the excessive viscosity of the ink. .
2, after the bubble is generated, plus defoamer is a direct and effective method, but it should be appropriate. Adding too much defoamer will make the ink particles thicker, and the flexible plate will have small dents and cracks.
3, the use of positive barrier, appropriate to increase the speed, so that the bubbles can not easily transfer to the anilox roller, reducing the chance of bubbles close to the anilox roller.
4. Add self-made two-sided ink barriers to prevent bubbles from entering the area behind the anilox roller from both sides, reducing the chance of bubbles transferring from behind to the anilox roller.
5, using artificial blister method. When the machine stops, the ink in the ink fountain stops high-speed turning, the bubbles in the ink slowly float to the surface of the ink, and bubbles are chipped with cardboard to reduce the number of times the anti-foaming agent is added, thus maintaining the printability of the ink and reducing the appearance of the flexible version. Depression has a role.