Analysis of the possible causes of the printing color difference of food packaging bags

Bright colors and bright patterns are the basic requirements of food packaging bags. How to avoid deviations between the finished product and the design manuscript after printing must first find the cause of the color difference and prescribe the right medicine. 1. Printing color difference caused by pressure discomfort The ideal printing process is based on the 'three flatsWhen the printing pressure is insufficient or uneven, and there is a bad contact between the lining body and the printing plate surface, it is necessary to increase the ink delivery to meet the visual effect of the ink on the plate surface, but this will not only increase the consumption of ink , It is easy to produce printing color difference and printing quality problems. 2. Printing color difference caused by poor ink rollers. Generally, there are three types of ink transfer rollers, ink distribution rollers, and ink application rollers on the machine that prints color prints. Among them, the ink transfer rubber roller and ink application roller have a greater influence on the ink density. The elasticity, viscosity, roundness, hardness and surface finish of the ink roller largely determine the ink quality of the printed product. If the inking roller has poor elasticity, insufficient viscosity, eccentric roller body, over-hard colloid, and poor colloidal finish, it is easy to cause uneven or unstable ink brushing during the printing process, which will cause the printing ink color of each printed sheet to be inconsistent. 3. Printing color difference caused by poor ink supply device. When the center of the ink fountain iron roller is poor or there is abrasion deformation, the ink fountain steel plate also has abrasion deformation, and the mechanism that controls the rotation of the ink fountain roller has defects, which makes the ink delivery in the printing process unstable. It can also cause color difference in printing. In addition, attention should be paid to the proper ink supply device. The ink in the ink fountain should be increased or reduced in an overall manner. There are two adjustment methods. One is to adjust the gap between the ink fountain steel sheet and the ink transfer (ink supply) iron roller; The second is to achieve by adjusting the rotation arc of the ink transfer roller. 4. Printing chromatic aberration caused by poor dampening. If the lithographic printing process is not suitable for dampening, printing chromatic aberration is likely to occur. In addition, if the water roller melt sleeve is used to age or absorb ink or impurities, it will affect the water absorption of the water roller and the uniform transfer of the fountain solution. Furthermore, if the water hopper device leaks, it will also affect the uniform transportation of moisture on the printing plate. The existence of these undesirable conditions will destroy the uniform and stable transfer of the ink on the layout, and cause differences in the ink color of the printed product. 5. Printing chromatic aberration caused by poor ink The thickness and viscosity of the printing ink are not easy to produce chromatic aberration. When printing, only a moderate and uniform printing ink layer can better guarantee the ink quality of the printed product and effectively prevent the occurrence of printing stickiness. 6. Printing color difference caused by poor substrate material In the food packaging bag printing process, we can find that the difference in substrate material is also one of the causes of printing color difference. For example, the difference in substrate gloss and hue will cause printing color difference. Taking embossed aluminized paper as an example, differences in the hue of the aluminized paper surface will cause inconsistencies in the color rendering effect of printing. Seven, the color difference caused by the bad machine, the worker must first sharpen his tools if he wants to do his job well. Maintaining the good performance of the machine is a reliable guarantee for improving the quality of printing ink. However, if the machine has bad conditions, it is most likely to cause the problem of printing color difference. Therefore, we should always pay attention to the maintenance and maintenance of the equipment, and pay attention to the lubrication of the key parts of the machine. 8. Printing chromatic aberration caused by poor printing plate Printing plate is one of the basic elements of the quality of graphic reproduction. In the printing process, the printing plate can only be maintained without deformation and wear in order to better ensure the stability of the ink transfer on the layout. During the printing process, if the dot layout appears to be pasted or deformed by abrasion, the lines are worn and enlarged. In this way, due to the change in the ink absorption of the layout, the ink color of the food packaging bag will inevitably be biased. 9. The difference of the characteristics of the light source and the observation angle on the identification of the color of the printed product. Usually the light source of the ink color of the printed product is identified, mainly sunlight (natural light), fluorescent lamp and incandescent lamp. They have different characteristics of the light source, and the color of the emitted light is also different. For example, the sunlight is mellow white, and the observation of the color is relatively accurate. The light of a fluorescent lamp is white with bluish, similar to sunlight. However, the light of incandescent lamps has red and yellowish colors, so it is difficult to accurately identify colors. Although daylight and fluorescent lamps are somewhat similar, the difference between the two should also be considered when identifying higher-quality color products. Heat shrinkable film manufacturers, food packaging film bag manufacturers direct sales-plastic bags The difference between POF heat shrinkable film and PVC heat shrinkable film, which materials are there for environmentally friendly heat shrinkable film?