In the field of anti-counterfeiting printing, paper anti-counterfeiting is at the top. At present, there are mainly several kinds of anti-counterfeiting printing paper, which have special anti-counterfeiting characteristics.
Watermark paper
It is a paper with relief, touch image, barcode, etc. Banknotes use the technology of watermark and anti-counterfeiting. Because watermark can not be reproduced by the photocopier, scanner, etc., its anti-counterfeiting effect is paid great attention to. Nowadays, the application of watermark has been extended to negotiable instruments, documents, even books, and periodicals. Watermark is in the process of papermaking, using technology to put the required logo, pattern, and others into the paper, such as installing a previously designed floating watermark graphic and text plate on the screen or pressing it by printing drum. Because of the different images and text, the pulp forms different densities of thickness. After the paper is formed, the paper has different transparency due to the different densities of the pulp in the text and text. Therefore, the original design of the picture and text can be displayed when the light transmission is observed.
There are three kinds of floating watermark, which are fixed watermark, semi-fixed watermark, and unfixed watermark. The printing process of the fixed watermark is difficult, and it must be fixed in a certain position of the main body such as banknotes, certificates, and certificates, and it is usually necessary to match the printed text or other anti-counterfeiting measures visible to the naked eye. The distance and position of each group of semi-fixed floating watermark are fixed, and each group is arranged continuously on the paper. Therefore, it is also called a continuous floating watermark, which is mostly used for special paper. The floating watermark is not fixed distributed in the full version of paper or face, so it is also called the full version.
The anti-fake watermark paper has developed from the original long net paper to the high-security long net paper, and its features include:
1) Up to 15 gray levels, there are many layers; the thickness of the black watermark area can reach 40 μ, which is thicker than the average thickness of 15-20 μ paper, so it has better contrast and has better details and clarity of the watermark.
2) Can obtain the long net paper does not have additional safety measures, such as safety line. The long cotton fiber is added to the pulp to improve the service life of the paper. On the paper machine, the watermark is formed on the surface of the watermark by fiber pile, and the watermark is formed simultaneously with the paper. This means that the watermark can be filled into the circular network model to form a very clear watermark.
With the development of electronic technology, electronic watermark paper is introduced. A system called microbar, which uses chaos theory to compile data into ciphers and add them to the background of documents. This kind of "micro bar" is invisible to the naked eye, but it can be read by the scanner and its password can be cracked. Only the original printing plate can be printed, any precision printing equipment can not copy or print some blurred images.
Including safety line anti-counterfeiting paper
Refers to the paper-making process in the middle of a gold or plastic line. The first user is a special metal wire, now use polyester plastic wire, micro letter safety line, fluorescent safety line, etc. The shape of the safety line includes a straight line, wave shape, serration shape, etc. According to relevant data, the new version of the US notes not only embedded in metal wires in the paper but also the line miniature can only be seen with high magnification. In recent years, the thermal safety line has been introduced, which is pink and opaque at room temperature. When the temperature is increased to 37 degrees Celsius, the printed text will be displayed on small scale. Another safety line, the laser holographic safety line, changes color due to different viewing angles.
Put a safety line on paper, the width of the line can be as small as 1mm. If multiple safety wires are put in at the same time, the distance between the lines can be as small as 4mm. The safety line can print the user's needs of the pattern and text, according to the different requirements of the different difficulties of anti-counterfeiting, the printed patterns and words can be made into a wishful or nonwishful space.
The safety line in banknote printing is also the focus of the research in various countries: for example, the open window transmission safety line is adopted in the UK, the safety line of partial aluminum plating process is developed in France, the safety line of partial aluminum plating process is developed in France, and the fluorescent safety line is used in Finland. The biochemical anti-counterfeiting mark is a breakthrough in the development of anti-counterfeiting technology. Recently, foreign biological research machinery has been successfully developed, mainly printing secret records on the adhesive label to achieve the purpose of anti-counterfeiting. Digital deformation and anti-counterfeiting technology have also been applied in foreign countries. This technology is applicable to any printing products requiring Arabic digital. Deformation is realized by a computer, without any rules to follow, and identification is also through the computer.
Laser anti-counterfeiting paper
Laser anti-counterfeiting technology and paper were combined to make anti-counterfeiting paper. For example, the holographic image is made in a specific position of the banknote by using holographic anti-counterfeiting technology and special equipment, and the anti-counterfeiting performance is improved. Its characteristics are as follows:
1) Because the holographic pattern is directly made on paper, the plastic information layer is removed, so it is very rare to be copied;
2) The pattern on paper can be designed, plate-making and produced different materials and grams of paper (70-400g) required by the business, such as copperplate paper, cardboard, and cardboard, and can be offset printing and silk printing, etc. like ordinary paper;
3) The price is only slightly higher than that of ordinary composite gold and silver cardboard, which is equal to one-tenth of the price of holographic anti-counterfeiting trademark, and saves labor cost of labeling, so it is easy to be accepted by the business;
4) After being abandoned, it can be weathered in the soil and will not pollute the environment.
At present, laser anti-counterfeiting paper has played a role in packaging the printing of some cigarettes, wine, cosmetics, food, and so on. For example: in Shengli Oilfield, a kind of nonfilm holographic dark anti-counterfeiting printing-packaging paper has been produced near one of the aluminum foil composite materials factories. It has the characteristics of pre-printing and post-printing, and the whole paper can be designed and produced with a special version or an ordinary version laser anti-counterfeiting image, with a width of more than 800 mm. The design adopts the implicit design, even if it is covered with multi-layer ink, it can be seen clearly, and has an excellent refraction effect, which does not affect the design and printing theme.
Red blue fiber paper, color dot encryption paper
The paper is made of colored fibers such as red and blue or small pieces of color (dots) mixed in the pulp or scattered on the surface of the paper before the paper is not set. There is fluorescent reflection under ultraviolet light so that the paper has colored fibers different from the paper itself. The red-blue fiber and color point mixed in pulp are two kinds of color fiber and colorless fluorescent fiber. The former can be seen on paper with naked eyes, the latter and color points must be visible under ultraviolet light. The color of the former is red, blue, orange, etc. the shape can be thick and fine, and it can be long or short. Fiber and color dots are generally randomly distributed, so the density of the embedded dew is different. In addition to plant fiber, in recent years, metal foil, plastic circular small plate into pulp anti-counterfeiting. If Italian paper coins are covered with a metal foil invisible to the naked eye, a sound will be made when checked with a special recognizer. In addition, British research uses a special fiber to lay a small piece, then uses a specific light source to irradiate from a specific angle, obtains a stereo projection, and stores it into a computer, and then verifies the authenticity by checking the projection of the mark.
Copy proof paper
One is full absorption-type copy-proof paper, which is blue and brown-red on the outside. Only through light can the text be seen on the paper, and the copy is dark. But this paper is not easy to use every day. The other is to apply a thin layer of aluminum protection on the surface of the paper (but not affect printing). Because the aluminum protective layer can disperse or deflect the light of the photocopier, the copy is black. Some anti-copy paper will appear "copy" and "invalid" after copying, which can effectively prevent color copying important documents. In addition, there are also proofs that when the photocopier light is encountered, the paper will change color or display hidden text.
Paper with trace additives
Based on the principle of biological anti antibody specific reaction, a very small amount of anti-elements is added to the pulp or a part of the paper. The specific antibody was used to detect the specific antibody and identify the truth and the false by the color and fluorescence.
Chemical encryption paper
Special compounds are added to the pulp or when sizing on the surface of the paper. This kind of chemical encryption paper can be colored or fluorescent after being coated with a specific chemical reagent. A foreign ticket for a ball game is printed on this paper. When checking, only a pen soaked with a special reagent is taken, and it is shown in black on the mark surface.
Special anti-counterfeiting paper in ionic media
The super energy ion medium special anti-counterfeiting paper, which is a leading national special heavy ion accelerator, integrates the ion microporous technology and paper technology, solves the problems of effective certificate anti-counterfeiting and identification difficulties.