Everything in life is always used by everyone. Usually, I go to the supermarket to buy something. Basically, I use a composite soft bag. Sometimes I don't know what to buy, I might see this package is not bad. So there are all kinds of colorful bags. Uniform ink color and pure color are the basic requirements for the quality of packaging products, and printing color difference is a common problem in the quality of printed products. How to produce the printing color difference, the specific analysis, in order to prescribe the right medicine.
First, the printing color difference caused by pressure discomfort
The ideal printing process is based on the "three flats", in order to achieve a more uniform ink color on the printed matter by balancing the printing pressure with a thinner ink layer. When the printing pressure is insufficient or uneven, when there is a bad contact between the liner and the printing plate surface, it is necessary to increase the ink volume to meet the visual effect of the printing of the printing surface, but this will not only increase the consumption of the ink. , it is easy to produce printing chromatic aberration and print quality problems.
Second, the printing color difference caused by the poor ink roller
On the machine for printing color prints, there are generally three types of ink transfer rollers, ink-dispensing rollers and ink-collecting rollers. Among them, the ink-adhesive roller and the inking roller have a great influence on the ink color. The elasticity, viscosity, center of the circle, hardness and surface finish of the ink roller largely determine the quality of the printed ink. If the ink roller has poor elasticity, insufficient viscosity, eccentricity of the roller body, excessive colloid, and poor gel finish, the printing process may easily cause uneven or unstable ink, so that the printing ink colors of the sheets are inconsistent.
Third, the printing color difference caused by the ink supply device
When the center of the ink fountain roller is poorly deviated or there is wear and deformation, the ink-jet steel plate also wears and deforms, and the mechanism for controlling the rotation of the ink fountain roller has defects, so that the ink delivery amount is unstable during the printing process, and the printing chromatic aberration is also caused. In addition, attention should be paid to the reasonable strip ink supply device. The ink in the ink fountain should be increased or decreased in total. There are two adjustment methods. One is to adjust the gap between the ink fountain steel sheet and the ink transfer (ink feed) iron roller; The second is achieved by adjusting the arc of the transfer roller.
Fourth, the printing color difference caused by poor dampening
If the lithographic process is unsuitable, the printing chromatic aberration is also likely to occur. In addition, if the water roller jacket is used to age or adsorb ink or impurities, it will affect the water absorption of the water roller and the uniform transmission of the fountain solution. In addition, if there is water leakage in the water bucket device, it will also affect the uniform transport of moisture on the printing plate. These unfavorable conditions will destroy the uniform and stable transmission of the printing ink, which will cause the ink color of the printing to be different.
Fifth, the printing color difference caused by poor ink
Printing ink layer thickness and viscosity are not easy to produce print chromatic aberration. When printing, only a moderate and uniform printing ink layer can better ensure the ink color quality of the printed product, and effectively prevent the printing from sticking.
6. Printing color difference caused by poor material of the substrate
In the daily printing process, we can find that the difference in the material of the substrate is also one of the reasons for the printing chromatic aberration. For example, the difference in gloss and hue of the substrate will cause the problem of printing chromatic aberration. Taking embossed aluminized paper as an example, the difference in hue of the paper surface of the aluminized paper may cause inconsistency in the color development effect of the printing.
Seven, the printing color difference caused by machine failure
If a worker wants to do something good, he must first sharpen his tools. Maintaining the good performance of the machine is a reliable guarantee for improving the quality of the printed ink. However, if the machine has a bad condition, it is also the most likely to cause the problem of printing chromatic aberration. Therefore, we should pay attention to the maintenance and maintenance of the equipment, and pay attention to the lubrication of the vital parts of the machine.
Eight, printing color difference caused by poor printing
The printing plate is one of the basic elements of the quality of graphic reproduction. In the printing process, the printing plate can only ensure the stability of the ink transfer volume if it is not deformed or worn. In the printing process, if the dot layout is deformed by the paste or wear, the lines appear worn and enlarged, so that the ink color of the printing will inevitably deviate due to the change in the amount of ink absorbed by the printing plate.
Nine, the characteristics of the light source and the angle of observation are different to identify the difference in the color of the printed product
Light sources that usually identify the ink color of the print, mainly light sources such as daylight (natural light), fluorescent lamps, and incandescent lamps. They emit different light source characteristics, and the color of the emitted light will be different. For example, daylight is alcohol white, and the color is relatively accurate. The light of the fluorescent lamp is blue, similar to daylight. The light of an incandescent lamp has a yellowish color in red, so it is difficult to accurately identify the color. Although daylight and fluorescent lamps are somewhat similar, the differences between the two should be considered when identifying higher quality color products.