The highest state of anti-counterfeiting printing-banknote anti-counterfeiting technology
Banknotes play an important role in economic circulation, and people cannot live without banknotes in their daily lives. The quality of banknotes is gradually improving, and the anti-counterfeiting measures of banknotes are also changing with each passing day. The anti-counterfeiting technology used in banknotes also reflects the advanced level of anti-counterfeiting technology in a country to a certain extent.
Taking China as an example, counterfeit banknotes have never faded out of sight, and HD90 counterfeit banknotes have been panicking for a while. Is that the fifth version of our RMB that can really be forged by criminals? I think that is impossible. If you carefully identify the HD90 counterfeit banknote, you can still easily find its flaws.
1. Paper security
First of all, from the bank notes, the criminals cannot get the special paper strictly controlled by the state. Banknote printing paper is specially manufactured by the country and has the characteristics of toughness, strong wear resistance, good stiffness, no lint, no breakage, no deformation after washing. Generally, banknotes are made of cotton and hemp and other raw materials after high-temperature cooking. Some countries will also add their own unique products to banknotes to achieve anti-counterfeiting purposes. For example, Japan adds Sanya leather pulp to pulp.
In addition to the texture of the paper itself is different from ordinary paper, a part of the color fluorescent fibers are also distributed in the banknote printing paper. The 1999 banknotes of RMB are randomly distributed with red and blue fluorescent fibers, which are clearly visible under ultraviolet light. This technology is also used in US and Canadian banknotes. From the 1885 edition, red and blue colored fiber yarns have been added to US banknote paper. The red and blue colored fibers of the US banknotes from the 1885 edition to the 1928 edition are directionally applied. The red and blue fibers are distributed in the middle of the banknote, forming two narrow strips from top to bottom. The red and blue colored fiber filaments in the 1928 edition and subsequent editions are randomly distributed throughout the banknote.
If the red and blue colored fibers need to be observed with ultraviolet light, the watermark on the banknote paper can be observed with the naked eye only by transmitting light. The watermark is a fixed pattern formed by the watermark roller in the papermaking process. Due to the different density of the fibers in the watermark area of ​​the paper, the light transmission and observation can see the patterns with different brightness and strong three-dimensional sense. According to the different positions of the watermark on the paper, it can be divided into full version watermark and fixed watermark. For example, the fourth version of the RMB one-yuan voucher is the full version of the watermark, the 80 and 90 versions are the full version of the ancient coins, and the 96 version is the full version of the five-pointed star (a big four small five-pointed star), and like the ten, twenty, Wu Shiyuan and Hundred Yuan are fixed watermarks. Compared with the full version watermark, the fixed watermark is more difficult to produce because the fixed watermark is accurately positioned on the paper. In addition to the different positions of watermarks, their production levels are also very different. Japan ’s watermarking technology has been deeply researched since the 1950s, and no one can compare it until now. The craftsmanship is superb.
The security thread is also an important anti-counterfeiting element on banknotes. The security thread is a special metal thread or polyester plastic thread of different colors, micro-printed thread or fluorescent thread embedded in a specific position of the paper. When the light is observed, a complete or intermittent (window opening) line is buried in the paper base. The shape of the line is generally a straight line, and it can also be made into a wave shape, a sawtooth shape, and the like. The window-type security wire is intermittently exposed on the paper surface. When copying with a copier, the exposed metal wire is copied into an intermittent black line, so it cannot be copied. The safety line can be designed in various colors, and can also be in the same line on a two-color interval. There can also be microtext on the line. For example, the US dollar is a fully buried security line. The security line is a polyester material called Myra. Under ultraviolet light, the security lines of different denominations show different colors, and English and numbers are also printed on the security line. Currency value. The security line of the RMB is window-opening, and some security lines on the window opening are printed with holographic currency values, such as ¥ 50 and RMB100.
2. Anti-counterfeiting of ink
A large number of special inks are used for anti-counterfeiting in banknote printing. One of our common types is interference-type optically variable ink. This ink has a metallic effect and pearl-like gloss. The ink color blocks printed on paper are usually a pair of colors, such as green-blue, cyan-green, magenta-green If the ink print is tilted to a certain angle, the printed part can change from one color to another when viewed under light. The anti-counterfeiting of the ink is very easy to identify, and because it has a dynamic change effect, it cannot be copied using high-definition copiers, color scanners, and other equipment. In addition, the manufacturing process of the ink is complicated, the technology is professional, the equipment investment is expensive, and the forgery is low, so there are a variety of banknotes that use this color-changing ink. For example, 100 yuan in the lower left corner of 100 yuan, green on the front and blue on the side; 50 US dollars and 50 on the front, gold on the front and green on the side; color blocks with color-changing ink printed on the French franc are green on the front It is blue when viewed from the side.
Another anti-counterfeiting ink is colorless fluorescent ink. In general, you may not pay much attention, but it will show dazzling colors under ultraviolet light. For example, the rectangle "100/50/20/10/5" appears under the ultraviolet light on the upper left side of the renminbi, emitting a strong bright orange fluorescence. Some counterfeit banknotes will also show fluorescent characters under ultraviolet light, but there is a big gap between the color depth and the fluorescence intensity, and the color is dull.
There is also an ink that looks not bright in color, but the instrument detects magnetic response, and some money detectors are designed and manufactured according to this principle. The horizontal number in the two-color crown in the lower left corner of the RMB is printed with magnetic ink. The gravure printing ink on the front of the US dollar is magnetic and can be detected with a magnetic detector.
At present, there is an ink that has not been used in RMB printing, but it is used in euro, Hong Kong dollar, Japanese yen, Canadian dollar and other banknotes, that is, pearl ink anti-counterfeiting. Pearlescent ink is a patent of Merck, the ink has a pearl-like luster, and the flash effect is magnificent. And this ink has interference color and transmission color, the color is bright and changeable. The pigment of pearlescent ink is formed by coating metal oxide on mica. The type and coating thickness of metal oxide determine the color of pearlescent pigment. Wrap mica with white titanium dioxide. When the thickness of the coating layer is 60 microns, the interference color of the pigment is silver-white, and the transmission color is colorless. At a thickness of 90 microns, the interference color of the pigment is golden, and the projection color is purple.
3. Printing technology anti-counterfeiting
Most of the layout design of banknotes is mainly based on characters, landscapes, paintings, architecture, etc., and is printed with complex and changeable shading. The printing method mainly uses offset printing, gravure printing, letterpress printing and special printing. The printing of the main scene is mainly realized by hand engraving gravure printing method. The gravure printing is a high-precision metal gravure hand-carved by the engraver. The pattern printed by this lithography is a three-dimensional pattern, which floats on the paper surface. There is a bumpy touch, such as the head of Chairman Mao on the RMB, and the touch is obvious, especially the hair and clothing decoration parts, under the magnifying glass, the line ink stands on the paper. Hand-carved gravure is an easy-to-recognize anti-counterfeiting method, and it is not easy to be copied. Hand-carved plate-making is difficult to be copied by Others because of its different knife skills, styles and unique skills. Therefore, it is difficult for others to imitate the true-to-life. It is also difficult for the author himself to engrave two identical plates. So far, it is an indispensable means of anti-counterfeit banknotes. Gravure printing can also realize a printing technology called refraction latent image. This technology makes use of different horizontal and vertical gravure lines' different effects of light tilt to make two kinds of graphics on the same part of the paper. When looking at this kind of picture and text against the light source, there is a kind of picture and text, such as when the paper is rotated horizontally by 45 degrees or 90 degrees, it will be transformed into another kind of picture and text. This technology is used in passports of Canada, Sweden, Czech Republic and other countries. The ellipse-shaped flower on the upper right of the front of the fifth set of 100 yuan bonds in China can be rotated through the above-mentioned angle to reveal the invisible denomination number "100".
Lithographic offset printing is used to print complex and variable shading of banknotes. Lithographic offset graphics and paper are almost on the same plane. Most of the prints we see use this technique, but lithographic offset printing also has printing techniques that are difficult to imitate, such as microtext offset printing, multi-color overprinting, and cross-printing. Technology and pattern docking technology. The microprint offset looks like a solid line or dashed line to the naked eye, but under the magnifying glass, it is a small and clear text. Shading multi-color overprinting uses several colors of ink to overprint the same pattern, thereby forming an overlap of multiple colors and making the pattern colorful. This is a high-precision offset printing technology that is generally difficult to imitate. Both the printing and the pattern docking have put forward extremely high requirements for the offset printing accuracy, which is a great test for the accuracy of the printing machine and the printing person's technology.
Relief printing is a printing method in which the graphics and text on the printing plate are higher than the layout. When printing, the graphics and text are partially inked, and the paper is pressurized, and the ink is transferred from the printing plate to the paper surface. The pressure during printing causes raised marks on the back of the paper. This type of printing is generally used for the printing of bank notes. It is also a kind of anti-counterfeiting.
Special printing methods include rainbow printing, wiring printing, shading anti-copy printing, hologram printing, etc. The main color or background of the pattern is composed of different colors, but the color transformation of the lines or images is gradually transitioned, without obvious boundaries, just like the gradient of the rainbow colors of the sky. The color of the background shading on the front side of China's 100 yuan is gradually changing from orange to orange, red, green and blue, which is the application of this technology. Wiring printing is that two colors appear on the same line of the ticket pattern to connect with each other. The two colors at the connection can neither be separated nor overlapped, which requires sophisticated equipment and superb craftsmanship. China has been able to complete the precise docking of four colors and patterns at one time. Holograms, visualizations, and shadings are all new anti-counterfeiting technologies developed to prevent counterfeiting of counterfeit banknotes by modern copying technologies, such as the anti-copy shading of the US dollar after 1996, and the portrait and building backgrounds are composed of equidistant arcs The composition, no matter what method is used for copying, will produce regular diffraction fringes, such as the constellation anti-copy technology in recent years.
Ningbo Yinzhou Hengxi Winbate Household Product Manufacturer , https://www.winbatehousehold.com