Talking about the factors to be considered in the determination of the dry oil addition and discharge amount and prevention countermeasures (2)

The disadvantages caused by improper addition and release of dry oil and their solutions

Dry oil has a great influence on the imprinting drying of the printed matter. Adding too much ink will make the ink dry too quickly. Adding too little will make the ink dry too slowly, and ink drying too quickly or too slowly will have some adverse effects on the printed matter. Many difficulties and shortcomings in printing are summarized below for some common defects and solutions:

1, dry oil and put too many problems and solutions:

1 Ink particles become thicker and tend to accumulate on the printing plate graphic part and the blanket;
2 The blank part has increased fat content, the viscosity of the ink is increased, the layout is dirty, and sometimes the PH value of the medicine is too high;

The above two conditions cannot be solved by strengthening the acidity of the water bucket medicine. Add some amount of Vaseline or No. 70 dry oil produced by the Shanghai Ink Factory to the ink, and the amount of dry oil added is generally controlled at about 1-5%. Should the situation be severe, the ink on the roller should be washed off, and then the remaining ink should be put in a suitable amount of new ink (not dry oil) and mixed before it can be used.

3 The ink flow is reduced, the printing plate is unevenly inked, and the “skinning” and “pulling” phenomena occur during the printing process of the paper.

This situation can be added to the ink No. 6 varnish and No. 70 dry oil to increase its fluidity and improve the drying performance of the ink.

4 premature conjunctiva products, so that the imprinting surface of the glass (crystallization) phenomenon, so that the surface of the blot is very smooth, lost the adsorption capacity, the latter color can not be printed.

In this case, if the number of prints is small, tooth powder (magnesium carbonate) may be attached to the cotton ball, and the surface of each print may be gently scratched to destroy the surface conjunctiva and then overprinted.

If the number of printing is large, you can use a solution of alkaline water to solve it. The specific operation is as follows: 0.5 kg of edible alkali, 15 kg of water, boil the water, put the food alkali into the water, stir well, and put the alkaline water Pour into the water hopper and pass the crystallization product over the machine so that the conjunctiva that is crystallized on the surface of the print is destroyed to facilitate the next overprint. After over-alkali water, it is easy to make the paper stretch. In order to avoid elongation of the paper, overprinting is inaccurate. Therefore, the best method is to carry out double-color printing on one side. To prevent the alkali water from being too strong, burn the roller.

The following methods can also be used for printing: 0.5 kg of ink, 2% of white dry oil, 1 kg of red dry oil, 10% of 5% N2OH solution, and mix after use.

5 The high concentration of water bucket solution causes the print to quit:

This situation can be added in the remaining ink, add appropriate amount of new ink and mix, while reducing the acidity of the water bucket solution.

2. The disadvantages caused by dry oil addition and release are too small and solutions:

1 Imprinting is not easy to dry, affecting the smooth progress of underprinting;
This kind of situation must stop quickly, adds the appropriate amount of dry oil in the ink fountain, causes it to speed up the drying speed.
2 Imprinting is blurred, and it is easy to produce "powdering" phenomenon, and the product is dull;
This situation should be appropriate in the ink dry oil, it is best to mix red and white dry oil, to help the ink surface of the good conjunctiva, but pay attention to light-colored ink should not be added red dry oil, so as not to change the pale red oil dry ink The hue.
3 printed back adhesive;
The back of the printed product, especially the printed copperplate paper, is prone to happen. This condition should be prevented in advance. Dry oil must be added properly when the ink is transferred. Add some anti-adhesion agent to the ink, and then use the air-drying version, dusting, etc. Measures to solve.

Conclusion

In the case of dry blots, there are various signs in the printing process. Some unfavorable factors also have signs. The following signs should be introduced:

1 Ink roller and ink fountain have no signs of early drying;
2 The use of lead salt driers, the degree of yellowing of the layout;
3Can you smell the special smell of ink drying?
4 Measure the dryness of the ink at the middle and the end of the ink roller. The effect of the dampening solution and emulsification on drying can be known.

The printed product can also directly reflect the drying of the imprint;

1 Because the drying process is an exothermic reaction and the product temperature of the paper stack is measured, it can be inferred whether it is dry or not;
2 shaken through the product if it smells dry;
3 products with a lot of ink, the printed sheets are fixed together and become hard blocks after drying;
4 The dryness of the sample is printed on the workbench, and the proportion of dry time can be known;
5 Sampling and inspection of product drying conditions;

All in all, ink properties are the basic conditions after all. As long as we constantly observe the drying conditions of ink at any time, we can promptly find out, take measures, adjust measures according to the time, balance various factors, accumulate data at any time, and constantly explore ways to use ink. The amount of oil that can be put in place can prevent diseases that are not (slowly) dry and dry too quickly and ensure smooth production.

Hubei Qinyin Printing Factory

Source: Print Information