5 Typical Cases to Teach You to Use Offset Ink

With regard to the practical application of ink, the author wanted to highlight the relationship between the correct adjustment of the ink and the quality of the printed matter through his own understanding of some of the most profound examples.

Case I: Bad ink overprint

When the company printed a batch of handbags, the magenta dots of the latter color group and the cyan overprint of the former color group were poor, resulting in many pie spots on the printed products. Although the author has repeatedly lowered the viscosity of magenta ink and hopes to increase the rate of superimposition, it has no obvious effect. Without help, we have to reverse the order of cyan and magenta so that the issue can be completely resolved.

Case study: multi-color printing machine is done in a very short period of time, ink trapping method is wet on wet, if the printing color sequence arrangements properly, its ink trapping rate will decline. Therefore, the following basic principles should be followed when arranging its printing color sequence according to the characteristics of the multi-color machine.

(1) According to the ink transparency arrangement printing color sequence. First, the ink with lower transparency is printed, and the ink with higher transparency after printing is used. This can improve the color rendering effect of ink after overprinting.

(2) Arrange printing color sequence according to the area of ​​printing plate graphic. That is, the printing area has a small ink-printing area and a large area of ​​ink-colored printing.

(3) Arrange printing color sequence according to the ink viscosity. The ink with a large viscosity is printed first, and the ink with a small viscosity is printed afterwards, and the viscosity of the ink is reduced one by one in turn. If the ink with high viscosity must be printed on the latter color group, the viscosity should be reduced firstly with a de-bonding agent, otherwise, reversed overprinting failure will occur, that is, ink color mixing occurs. For example: When the machine's gripper teeth wear, black ghosting failure, you can adjust the color sequence, the black ink arranged in the second, third or fourth color group printing, but in time to reduce the viscosity of black ink.

(4) Arrange printing color sequence according to the characteristics of the original. For example, when printing manuscripts mainly composed of warm colors, such as Caixia, the cyan should be placed in the former color group, magenta should be arranged behind, and the manuscripts such as glaciers and snow scenes mainly composed of cold colors should be placed in magenta. In the former color group, cyan is arranged behind.

In the above case, the cause of the malfunction is that the cyan ink is on the ground and the ink layer is thick, while the magenta ink is a light mesh, and the ink layer is thin. When the magenta ink is printed on the wet and thick cyan ink layer, ink will certainly be produced. The phenomenon of overprinting is poor, and printed dots are floating and irregularly increasing. As a result, markings appear and are very unfair. When the color sequence is reversed, troubleshooting is performed.

Case No.2: Overprinting due to ink stripping tension on paper is not allowed

When a machine is printing a full version of beef paste brand (80g/m2 single coated paper), it is always overprinted, and the fourth color group is constantly sticking and peeling. There is a long-standing problem with tooth decay, and repeated cleaning and lubrication of tooth decay can still not be resolved. After reviewing this article, the viscosity of black, magenta, and yellow inks was first reduced with a de-bonding agent, and then the printing pressure of each color group was reduced as much as possible, and troubleshooting was eliminated.

Case Study : For a full-size version of a large amount of ink, the ink viscosity and printing pressure must not be too large, otherwise, once the paper is thin, the paper will be difficult to overcome the excessive peel tension, resulting in overprinting, paper curl, Even the tusks were unable to peel off the paper from the blanket to complete the normal transfer, so that the paper was continually torn and peeled. When the author took the measure of adding de-bonding agent and reducing the printing pressure, the stripping tension of the ink on the paper was greatly reduced, and the production can naturally proceed normally.

Case 3: The ink's color rendering effect is dark

There is a four-color bank deposit book, and the main color of the book cover is overprinted by 100% yellow and magenta. When customers sign on the machine, they think that the overprinted red is somewhat dark, which is a far cry from the effect of the bright and pure gold color, and does not agree with formal printing. Faced with this situation, the author is very difficult, because if you re-plate, the time is too late, and it will increase the cost, so you can only use your brain in ink stacking.

Later, according to the change of the color of the ink, the author decided to change the medium yellow used in the four-color ink to light yellow and the magenta to red. When the first sample was printed, we found that the main color of the cover of the passbook had fully achieved the effect of gold and red, the color was very bright, and the customer was very satisfied.

Case Study : It is undeniable that in the commonly used three primary inks, due to factors such as cost and price, different batches of inks have certain deviations in hue, such as yellowish reddish, magenta yellowish, and sky blue reddish. Overprinted colors, whether red or green, have lower color saturation and greater gray levels. At this time, we must analyze the originals, seize the most important colors, select the most suitable ink, and print the best results.

Later, based on this successful experience, the author also adopted a combination of pale yellow ink and hole blue ink respectively, printing a relatively pure green, so that customers are very satisfied. This method can also sometimes correct some color cast problems on the plate, and achieve unexpected results. Such innovations are quick and easy, and do not require any additional cost.

Case 4: "Ghosting" caused by ink

On one occasion, the machine platform printed a cover for an early childhood book. The mouthpiece of the printed product was a pattern of small trees. The tip of the print was a pattern of a large apple. During the printing process, it was found that there was a "ghost image" of the small leaves in the mouth of the apple pattern at the tip. At first, we thought that there was a problem with the ink path of the cyan group. We first adjusted the pressure of the water and ink rollers of the color group to the standard. As a result, “ghosting” still existed. Therefore, we re-adjust the relevant parameters of the back yellow group, and the result is still not enough. After calm thinking, the author guessed that it was caused by ink, so immediately added 3% of the detackifier to the yellow ink, and then started printing. The "ghosting" immediately disappeared.

Case Study : We know that the main reason for the “ghosting” is the improper design of printed products and poor ink transfer. In this case, there is no such problem. From the printing color sequence arrangement, the yellow ink has the highest transparency and the lowest stickiness, and printing on the last color group is correct. And we use high-grade, environmentally friendly inks that are ready for use without any additives. Why did it happen at this time?

Originally, due to the large difference in the graphic area of ​​the four-color printing plate, the consumption of the blue ink is small, the ink on the roller is replenished little, and it is continuously eroded and emulsified by the fountain solution, and the ink viscosity is greatly reduced; The yellow ink consumes a large amount and can be continuously supplemented with new ink. The viscosity of the ink does not change much. When the machine is under pressure, the yellow ink sticks to the blue ink remaining on the blanket under the effect of printing pressure, forming a slight reverse overprint, and then transferring through the yellow group by the printing roller, There is a "ghost image" of small leaves in the apple pattern. In other words, the viscosities of the two inks are relatively close to each other, which leads to the production of “ghosting”. When the writer adds the detackifier to the yellow ink, the viscosity of the yellow ink drops a lot and “ghosting” naturally disappears.

Case 5: Poor ink transfer, printed ink

The common causes of fading ink color are: (1) the ink supply is too small; (2) the ink is over-emulsified to form an oil-in-water state, resulting in a lighter print; (3) uneven pressure on the roller, or adhesive The surface of the roller is crystallized, causing the ink to be unable to transfer normally; (4) The printing plate graphic part is poor in ink affinity, or the printing plate graphic part produces a flower plate due to wear during the printing process, which makes the printing ink color light; (5) Blanket pile paper powder, aging, etc., leading to poor transmission of ink.

Regarding the above issues, we have the means to solve it quickly, but there are also some special circumstances that require careful analysis and patience. A captain of a four-color machine of our company found that the ink of the printed product was very light when printing a certain book, and even if the conventional measures such as reducing the amount of water supply and increasing the ink supply were taken, it would not help. When the captain reported the situation to the author, the author immediately came to the scene and found that the ink on the rubber roller was indeed a lot. As long as the machine was slightly jogged, he could hear the ink separating on the roller.

Hair Mask Masque

hair mask

DELIN HAIR COSMETICS , https://www.arganshampoofactory.com