Gold sweeping technology in the hottest surface fi

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Gold sweeping technology in surface finishing the processing of gold imitation effect is one of the effective means to improve the grade of commodity packaging. At present, there are mainly gold ink printing, frosted printing, bronzing and gold sweeping. Each method has its own characteristics. The following mainly talks about the gold sweeping technology

1 what is the gold sweeping technology

the so-called data gold displayed on the instrument after sweeping is a process to achieve the metal luster effect by attaching special metal powder to the designated part of the commodity packaging or label printing through a special process. This technology can get realistic metal texture and better gloss, and fine pattern and accurate overprint

2 application of gold sweeping technology

the gold sweeping technology is widely used in the packaging of cigarettes, wine, drugs, cosmetics and high-end food, as well as the printing of greeting cards, invitations, calendars and other products, which can greatly improve the added value of commodities. In the 1990s, China's gold scavenging technology has developed to a certain extent. Some areas with developed packaging and printing (such as Guangdong) have also introduced several gold scavenging machines, which are mainly used for making cigarette packets and medicine packets. With the improvement of packaging requirements in China, gold sweeping technology will have greater development

3 gold scavenging process principle

the gold scavenging process is actually very simple. Put the printing sheets that need gold scavenging on the monochrome or two-color offset press, and use a special PS plate to print and apply a layer of adhesive on the parts that need gold scavenging, so that the Jinan laboratory machine industry can rapidly expand the adhesive. Then the printing sheets enter the gold scavenging machine through the paper feeding device, sweep the gold powder, polish and wipe the gold

at present, the Jazz brand automatic gold sweeper produced in Germany is mainly composed of five parts: paper feeding mechanism, coating mechanism, polishing mechanism, cleaning mechanism and paper receiving mechanism. The printing products can be processed from thin paper to paper jam, from four open to full sheet, and the speed can reach 8000 sheets/hour. A flat sheet single (double) color offset printing machine (removing the paper receiving device) is generally required to be connected with the gold sweeper during gold sweeping. First, the special PS plate of the gold sweeper is made, installed on the offset press and adjusted. The PS plate is used to print a thin and uniform primer on the part where the gold powder needs to be applied on the printed matter, and then the printed matter is sent to the aspirated rubber conveyor belt of the gold sweeper through the paper transfer device of the gold sweeper. The gold powder is uniform and coated on the surface of the printed sheet through the coating mechanism. When the gold powder adsorbed on the cloth roller is turned to the top of the printing sheet, this part changes from suction to blowing, and the gold powder is evenly sprayed on the whole surface of the printing sheet. The four polishers of the polishing mechanism rub and polish the gold powder on the printing sheet, so that the gold powder printed with the primer on the printing sheet is firmly adhered. At the same time, the gold sweeper also uses four special gold wiping tapes, which reciprocate with each other to improve metal luster and bonding fastness. The last two are equipped with strong suction pipes, which can remove excess gold powder. The high vacuum adsorption multi-channel cleaning circulation system of the cleaning mechanism, together with the front suction pipe, can quickly clean up the excess gold powder on the printing sheet, which can be recycled without causing environmental pollution or waste. Finally, the paper receiving mechanism completes the paper receiving and finishing work

of course, if the printing plant has a multi-color printing machine and a UV drying device, online gold scanning can be carried out, that is, the printed pieces are printed in the first few colors of the printing machine, fully dried by the UV drying device, the primer is printed on the last color group, and then enter the gold scanning machine through the connecting device for gold scanning

4 characteristics of gold sweeping technology

compared with other processing technologies with gold imitation effect, gold sweeping technology has advantages in many aspects, but also shortcomings

1) compared with gold printing

at present, gold printing can adopt offset printing, gravure printing, flexo printing and silk screen printing, especially offset printing and gravure printing, both of which are relatively fast. Offset ink layer is thin, metal luster is not very good; Although the ink layer of gravure printing is thicker and the gloss is better than offset printing, the metal texture is not strong enough in large-area printing. It is easy to deform when printing small characters and fine lines, and the quality is not well controlled

2) compared with bronzing

bronzing, as a traditional gold imitation processing technology, has strong metal luster and metal texture. It is an indispensable processing technology for some high-end packaging at present. In this regard, it is better than gold sweeping. Although the quality effect of bronzing is good, most of them need to be heated and consume more energy. Registration is sometimes not easy, especially in some small graphics and large-area bronzing, the quality is difficult to control, the process is relatively complex, the cost is relatively high, and most of the bronzing equipment is slow and inefficient

3) compared with frosted printing,

although frosted printing has better metal texture and luster, its production efficiency is low, and the waste packaging is not easy to recycle, which is not conducive to environmental protection

4) advantages of the gold sweeping technology

 the gold sweeping technology has the advantages of simple operation process, fast speed and low cost. It can achieve good results regardless of the size of the picture and text and the size of the area

 after gold sweeping, the product has better metal sand feeling and light diffuse reflection effect, more realistic metal texture, and gives people a visually obvious three-dimensional feeling, which is different from gold printing and bronzing

 the color of sweep gold is rich and colorful. In addition to the most commonly used gold, there are silver, copper, green, graphite, Tan, lemon yellow and Malachite blue, as well as the diamond like motorcycle light alloy wheel radial impact testing machine widely used in Europe and North America, which is referred to as wheel impact testing machine or wheel radial impact testing machine stone gold powder and laser gold powder for short. These gold powders have different particle sizes and can show a variety of unique effects

 anti counterfeiting effect: as the effect of gold imitation obtained by gold scanning is different from that of gold printing, bronzing and frosted printing, it is unique, difficult to imitate, and has a certain anti-counterfeiting function

5) disadvantages of gold sweeping

although gold sweeping technology has very obvious advantages, it is not perfect

 the main feature of gold sweeping is to form a gold imitation effect at specific parts, but a single gold sweeping process is difficult to achieve the best metallic luster and texture at present, and it is not as good as bronzing in some aspects

 it is not as convenient as gold printing on printing sheets that need large areas of imitation gold, and it has no advantage in effect. Therefore, the overall size of the sample for gold scanning design; It is only a mid-range gold imitation effect processing technology, which has certain limitations, which limits its rapid development to a certain extent

 the gold sweeper has very high requirements for the environment. The temperature should be controlled at 22 ~ 25 ℃ and the humidity should be controlled at 50 ~ 55%. Otherwise, it is easy to have quality problems

the common faults in gold sweeping are dirt sticking and powder dropping. The main causes are as follows: ① too much humidity in the gold sweeping workshop or too high water content in the paper will cause the gold wiping belt to be wet and not clean; ② The imprint of the printed matter is not completely dry, resulting in gold powder sticking to the parts that do not need to be brushed; ③ There is insufficient viscosity of the primer or insufficient glue on the printing sheet where gold needs to be brushed, resulting in powder dropping

5 conclusion

it can be seen from the above analysis that although the gold scanning technology still has some shortcomings, its advantages are very obvious, especially in anti-counterfeiting, metal texture and advertising effect. At the same time, the cost of sweeping gold is relatively low, and the printing factory can obtain higher profits. Although there are not many domestic manufacturers using gold sweeper at present, with the continuous maturity of gold powder processing technology and gold sweeping technology, as well as the perfect combination of gold sweeping, bronzing and silk screen printing, it will play a unique role in the domestic packaging and printing industry, especially in the packaging of cigarette packets, wine packets, high-end drugs and food

source: printing world by chenwenge

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