The characteristics and improvement measures of on

Characteristics and improvement measures of bank card printing

compared with offset printing, the ink layer is thick, and the thickness is usually μ A year-on-year decrease of 47.81%; In addition to the exchange loss of 198 million yuan, the net profit attributable to the parent company is 2.458 billion yuan m, which is times the thickness of offset ink layer. Therefore, it has good weather resistance and drug resistance, bright colors, high density, and three-dimensional printing patterns, especially the printing effect of gold and silver ink, which is unmatched by offset printing. Bank cards mainly refer to magnetic cards and IC cards used in the financial system. This paper mainly discusses the printing process of bank cards based on PVC materials. Relatively speaking, bank cards have higher requirements on printing color, so it is particularly difficult to control bank cards. After often mastering the printing skills of bank cards, there is no difficulty in printing any other PVC cards

the following is a brief introduction to the technical characteristics of bank card printing

I. ink

solvent based soft plastic printing ink is usually used for card printing. Two factors must be considered when choosing ink: first, the adhesion between ink and substrate material should be strong; Second, the hiding power of ink should be high. This is the key to card printing ink. Adhesion mainly affects the adhesion fastness between ink and card substrate, while the strength of coverage mainly affects the printing quality

1. Inking

when adjusting the viscosity of ink, we must choose a solvent suitable for the ink, preferably from the same manufacturer as the ink. When adjusting, the addition amount should be moderate. If the addition amount of solvent is excessive, the ink viscosity is low, which is easy to flow to the back of the version, causing the card pattern to become blurred and refined; If the addition amount is too small and the ink viscosity is high, the printing will be blocked, and part or most of the patterns of the card cannot be completely reproduced. During the printing process, it should be noted that the viscosity of the ink will gradually increase with the volatilization of the solvent. Operators should often push the ink on the plate and constantly supplement the adjusted ink

2. Drying

the drying time of ink is different due to the size and characteristics of card patterns. Generally, the drying time of cards with full page patterns is longer, and that of cards with words and small color blocks is slightly shorter. It should be noted that after drying, do not print one color immediately, and it needs to be cooled for a period of time. Because the freshly dried card material has extensibility due to heating, it can generally be cooled for about 10 minutes. The growth of China's plastic machine industry has ushered in the golden age of Komen's growth and rapid growth. The effect of blowing cold air to printed matter is good

3. Color matching

when color matching, the number of colors of the ink should be less, which is generally used for interchrome. If you use too many ink colors, it is more difficult to call out the hue required for the year, so it is necessary to pay attention to the basic color for color matching

there are often a lot of bubbles in the blended ink. The ink with low viscosity will naturally defoaming after a certain period of time; For those with high viscosity, add about 1% defoamer and stir evenly to meet the printing requirements

II. The production quality of edition

1 and the selected edition plays a key role in the printing quality. Card printing generally adopts mesh/inch silk, which can basically meet the card printing of different inks and various patterns; However, when printing gold and silver inks, we usually choose mesh/inch silk. Because there are gold, silver powder and other metal particles in gold and silver ink, the selection of mesh mainly depends on the diameter of all gold coated particles. If the particle diameter is large, choose the wire with small mesh and large hole

2. Stretch

card printing general color aluminum alloy frame. When selecting the frame, pay attention to the flatness of the four sides of the frame and whether the frame is distorted; When re stretching the old frame every time, pay attention to grinding the frame with a grinding wheel. At present, there are many imported nylon yarns, and the elongation and grindability of domestic yarns need to be further strengthened

the tension of the four corners of each version should be consistent, and the tension of each set of versions should be consistent. The tension of the pre printing plate should be n/cm

in addition, the angle of tension is very important. Except that some full-size patterns can be 90 ° straight tension, general patterns should be inclined tension as far as possible, and the tension angle of 22.5 ° is the best. Oblique stretching can effectively avoid serration in the holes at the edge of the card pattern, and improve the clarity of graphics and text and printing quality

III. scraper

scraper is the most connected tool to push and transfer ink to the substrate in printing. Its structure is very simple, but it has a great impact on the quality of printed matter. The scraper is made of polyurethane, which has strong solvent resistance and good wear resistance, and can withstand high temperatures below 90 ℃. It is a solvent based ink very suitable for card printing

it is important to match the hardness of the scraper with the characteristics of the print. The soft scraper of SH is suitable for printing full page patterns; SH80 scraper is best used for lines and words with high accuracy requirements

the scraper needs to be grinded frequently. When printing the next color after printing one color, it is necessary to confirm whether the blade of the scraper is normal and whether the glue has a tendency to bend. The scraping angle, pressure, sharpness and smoothness of the blade have a direct impact on the printing quality, and the overall performance is quite loud compared with American 7085 alloy products, which requires operators to continuously accumulate work experience

IV. equipment

card printing equipment is mainly flat printing and roller printing. Plane printing machine is the earliest mechanized printing machine, which is widely used in semi-automatic and full-automatic models; The biggest feature of the drum press is that the printing table is cylindrical. Compared with the flat printing machine, the drum printing machine has higher requirements in operation and accuracy adjustment. Its printing speed is faster and the product quality is better. But no matter what type of printing machine, it is very important to adjust the distance (distance) between the plate and the plate table. Due to the small distance, the plate fails to snap well in time after inking, resulting in surface contact between the plate and the substrate, which is easy to cause ink seepage and dispersion, resulting in difficulties in inking; If the distance is too large, the surface that is not easy to recover will be loosened after the plate is extended too much during embossing, resulting in errors between the printing size and the layout, which has the greatest impact on overprint. In addition, the distance is also closely related to the size of the frame, the viscosity of the ink, and the tension of the plate

v. overprint

in card printing, it is often necessary to combine printing with offset printing, among which registration is a major difficulty. Due to the flexible plate printing with material thickness less than 1mm, and the different tension of each plate, it is easy to cause a certain error between the size of the printed card pattern and the size of the plate making film, which will cause a certain error between the size of the printed card pattern and the size of the plate making film. In this way, there are many hidden dangers for registration in the combined printing and offset printing

the simple improvement measures are: those who can use printing first should print first, and then use offset printing to catch up with printing sheets. Because of this, offset printing can be adjusted according to the actual size of printing. When the size of its mouth is different from that of the trailing tip, the vertical size of offset text can be adjusted by adjusting the blanket of the offset press and changing the thickness of the printing package; The horizontal size can be recombined with hydrogen plate making film according to the actual size of printing. After the above simple adjustment, the registration problem of printing and offset printing can be significantly improved. Of course, if the printing process, due to the destruction of the plate and other reasons, the change range of printing size needs to be adjusted in time

the bank card printing process will develop in the direction of UV ink printing in the future. It will have more advantages in the three-dimensional sense and color saturation of the pattern, and meet the requirements of environmental protection while improving the printing quality

reprinted from: keyin