The plate must be kept at a certain gap between the plate and the barrel so that it can be contacted only when the plate and the surface of the barrel are only used by the doctor blade during printing, and the blade is removed after passing. The size of the printing gap has a great influence on the printing quality, and the gap is not properly adjusted, and high quality products are not printed.
The printing gap is too small, and it is easy to cause ink squeezing in the direction in which the doctor blade acts.
Because the gap is small, it is necessary to increase the printing pressure, so that the printing plate will be slack due to excessive stretching, and the printed graphic will be out of shape, and the graphic size on the barrel is larger than the printing plate. The printing gap is generally 1 ~ 6 mm, the printing precision is high, the frame area is large, the screen is stretched tightly, or the curved surface is printed, and the value is small; the general printing, the frame area is large, the screen is stretched loose, and the plane printing is taken. The value is large.
3 printing speed and squeegee angle
The angle of the squeegee formed by the squeegee and the plate and the speed at which the squeegee moves should be kept constant. The angle of the squeegee is generally 45°~90°, and the printing speed is generally 100~300mm/s. The smaller the angle of the doctor blade formed by the printing plate and the doctor blade, the slower the moving speed of the doctor blade, and the more ink is pressed; the smaller the angle of the doctor blade, the better the ink is pressed out.
Smart cards are also called "integrated circuit cards", referred to as I C cards. It is made by encapsulating an integrated circuit chip module with storage, encryption and data processing capabilities in a plastic substrate. Smart cards can be divided into single-layer cards and multi-layer cards. Single-layer IC cards are produced by direct printing of single-layer PVC raw materials or by injection molding. Multi-layer I C cards can be divided into contact card, contactless card and combination card according to different structures and working modes.
1. Printing of smart cards
The printing of smart cards is basically the same as that of general magnetic cards. Currently, offset printing and screen printing are mainly used. Offset printing generally prints high-precision photos, patterns, etc., and can reproduce clear dots and very thin lines, with low plate making and printing costs, and clear text and images. The offset printing machine mainly has a special PVC card printing machine or an imported four-color printing machine. It mainly uses U V offset printing ink, and the printing color is bright and the graphic is clear, which is suitable for mass printing. It is printed on the P V C material first, then laminated, punched, magnetically written, embossed, etc., but the U V ink is used for offset printing, so that the protective film is easy to fall off. Therefore, a 2mm blank should be left around the plastic magnetic card during design. It is best not to use fluorescent ink. Pay attention to cutting or processing.
Screen printing has the characteristics of thick ink layer, good hiding power, rich texture, strong light resistance, bright colors, and good printability for inks and substrates. Therefore, screen printing is the main printing method for smart cards.
Smart card printing usually uses resin-based heat-curing inks and solvent-based soft-plastic screen printing inks. The selection of inks should mainly pay attention to the two factors of strong adhesion and high hiding power. This is also the key to the card printing. Adhesion mainly affects the adhesion of the ink to the card substrate, and the hiding power mainly affects the printing quality. Therefore, when adjusting the viscosity of the ink, it is necessary to select a solvent which is more compatible with the ink. When adjusting the ink, it is necessary to control the amount of solvent added. The solvent is too much, the viscosity of the ink is low, and it is easy to flow to the back of the screen, causing the printing pattern to become thicker and thicker; the solvent is too small, the viscosity of the ink is high, and the printing is easy to cause blocking. The net makes it difficult to completely reproduce the printed pattern. In addition, in the printing process, as the solvent evaporates, the viscosity of the ink will gradually increase. Therefore, it is necessary to pay attention to the ink on the screen often, and continuously adjust the ink to have a stable viscosity. The color of the ink should be based on the basic color, and the number of colors of the ink should be as small as possible. Generally, the color of the ink is 3 to 4 kinds. If you use too much ink, it will be more difficult to call out the ideal hue. In the blended ink, there are often a lot of bubbles. The ink with low viscosity will naturally defoam for a certain period of time; if the viscosity is high, it is necessary to add about 1% of antifoaming agent and stir well. The drying time of the ink is related to the size and characteristics of the IC card printing pattern. Generally, the full-page pattern has a long drying time, and the drying time of characters and small color blocks is slightly shorter. However, it should be noted that the freshly dried magnetic card is elongated due to the heat of the material, so it must be cooled (usually cooled for about 10 minutes) to print the next color. If the cold air can be blown to the printed matter, the effect is better. The quality of the screen production plays a key role in print quality. Because the domestic mesh is not ideal in terms of elongation and wear resistance, imported nylon mesh is often used. Screen printing generally selects 150-350 mesh screens, but for gold and silver ink printing, the size of all gold and silver powder particles should be considered when selecting the mesh number to ensure that it can pass through the mesh aperture. Usually 160 to 250 mesh is suitable. The frame of the net frame is made of aluminum alloy frame. The selection of the frame should pay attention to the flatness of the four sides and the distortion of the frame. When re-stretching the net with the old frame, use a grinding wheel to smooth the mesh frame. Pay attention to check the quality of the stretched screen, so that the tension of each set of screens and each of the four corners of the screen is consistent, and the tension is generally controlled at 14-15 N/cm. For the angle of the stretch net, except for some full-page patterns, the 90 ° straight stretch net can be used. Generally, the oblique pattern is used as much as possible to avoid the sawtooth shape of the edge of the magnetic card pattern, which improves the clarity and printing of the graphic. quality.
Practice has proved that the angle of the mesh is 22.5°. The scraper is preferably made of polyurethane, which has strong solvent resistance, good wear resistance and can withstand temperatures up to 90 °C. The scraper should be ground frequently. Make sure that the blade edge is normal for each print. The scraping angle, pressure, sharpness of the cutting edge and smoothness of the blade have a direct influence on the printing quality. In addition, the control of the scraping angle, printing pressure, hardness of the squeegee and printing speed of the squeegee will cause chromatic aberration. Failure, therefore, attention should be paid to accumulating experience and reasonable control during operation. Magnetic card printing is currently dominated by flat screen printing and drum screen printing. The flat screen printing machine is the earliest mechanized screen printing machine. It has a semi-automatic and fully automatic machine type. The biggest feature of the drum type screen printing machine is that the printing table is cylindrical. Compared with the flat printing machine, the drum type screen printing machine has a fast printing speed and good product quality. However, the requirements for operation and accuracy adjustment are higher. Regardless of the type of screen printer, it is important to adjust the screen distance. If the screen distance is small, the screen will not pop up in time after over-inking, which will cause the screen to be in surface contact with the substrate, which will easily cause ink to ooze, which makes it difficult to draw ink; the mesh distance is too large, and the screen is extended when embossing When it is excessive, it is not easy to recover and slack, which causes errors in printing size and layout, and has the greatest impact on overprinting, which may cause malfunctions such as overprinting. In addition, we must also pay attention to adjust and control the matching relationship between the mesh distance and the frame size, ink viscosity, and screen tension.
Since current screen printing cards generally only print simple text and graphics, high quality color patterns cannot be printed. Therefore, in order to produce a large-volume, high-quality magnetic card, the screen printing and the offset printing are usually used in combination, and the advantages of the two printing methods are taken to complement each other. Generally, the large-area colored portion is screen-printed, and the thin line or small-text portion is printed by a small offset printing machine to compensate for the shortage of screen printing. However, since the screen printing is printed by a flexible screen printing, and there is a reason that the tension of each screen may not be completely uniform, it is easy to cause a certain error between the screen printing magnetic card pattern size and the plate-making film size, thus, in the screen printing and In offset printing, there is a problem of registration errors. The solution to this problem is mainly to adjust the printing method. In general, you should try to print on the screen first, and then offset. In this way, the offset can be adjusted according to the actual size of the screen printing. When the size of the mouth and the tip are different, the longitudinal dimension of the offset image can be adjusted by adjusting the blanket of the offset printing machine, changing the thickness of the printing package, and the lateral dimension can be adjusted according to the actual size of the screen printing. . In this way, the registration problem of screen printing and offset printing is basically solved.
2. Anti-counterfeiting printing of smart cards
IC card as an important information media, the surface anti-counterfeiting treatment as an important part of the overall system release management needs to be carefully considered. The technical treatment of the surface of the card body is mainly color pattern printing. Most of the surface pattern printing of IC cards uses a lithographic offset printing process. The characteristics of the offset printing process on the plastic surface not only make the card artistically appealing and collectible, but more importantly, it greatly improves the precision, particularity and complexity of the production, and increases the difficulty and risk of forgery. Some simple monochrome patterns, text or anti-counterfeiting inks are also screen printed. In addition, special signs such as fluorescent security image printing, color-changing markings, laser-engraved signatures and images, micro-line techniques, complex holographic image markings, miniature borders, and security background structures can be used.
At present, color portrait PVC cards have been widely used. It can not only print different personalized photos, names and other personalized information on the card, but also change the previous functions of the plastic card, such as single function, easy to forge, easy to damage, easy to open glue, not waterproof, etc. It is solid, waterproof, with good image effect and versatile features, and can be used to identify attendance, access control, consumption and other functions in one. There are two kinds of PVC color portrait cards. One is to print directly on the surface of a blank card using a thermal transfer card printer, which is costly. The other is to print the content to a color inkjet or laser printer. On the special PVC film base, the finished product is produced by hot pressing, punching and punching by lamination method.
In order to improve the anti-counterfeiting effect of the IC card, there are now a multi-layer invisible photoelectric card, which is a significant improvement on the optical card with clear hole and the barcode card with clear code. The structure includes the card base, the connection coating, the information layer and the protective layer. , invisible layer and film. The card base is generally made of plastic materials such as PVC, ABS, PET, etc. The joint coating is generally made of PVC material. It is a special material that can firmly connect the information layer of the powder material with the card base material. And completely through. The information layer mainly uses carbon powder, and its optical properties have a great difference in infrared absorption compared with the card base material. The protective layer can be made of a thin PVC material to protect the information layer and the connecting coating from the invisible layer. The invisible layer can be used for materials having good infrared transmittance and low visible light transmittance, such as invisible inks, PVC films with deep color and infrared light transmission. Its function is to cover the area composed of information points under the invisible layer, so that it can not be discovered when visually, thus achieving the purpose of invisibility. The film can be used with a P V C film, which serves to protect the invisible layer from being exposed to the outermost layer, thereby improving the wear resistance of the card.
The multi-layer invisible photoelectric card can be printed with ordinary materials by using a common material, and the prepared information can be directly printed on the card base material by a laser printer. Finally, the multi-layer material is pressed into a card by a heat sealing lamination process to form an anti-counterfeit card. This card not only has hidden information layer, but also has good anti-counterfeiting effect by visually observing anti-counterfeiting information, and has the advantages of strong wear resistance, strong bending resistance, stable card reading, convenient manufacture and low cost.
The printing gap is too small, and it is easy to cause ink squeezing in the direction in which the doctor blade acts.
Because the gap is small, it is necessary to increase the printing pressure, so that the printing plate will be slack due to excessive stretching, and the printed graphic will be out of shape, and the graphic size on the barrel is larger than the printing plate. The printing gap is generally 1 ~ 6 mm, the printing precision is high, the frame area is large, the screen is stretched tightly, or the curved surface is printed, and the value is small; the general printing, the frame area is large, the screen is stretched loose, and the plane printing is taken. The value is large.
3 printing speed and squeegee angle
The angle of the squeegee formed by the squeegee and the plate and the speed at which the squeegee moves should be kept constant. The angle of the squeegee is generally 45°~90°, and the printing speed is generally 100~300mm/s. The smaller the angle of the doctor blade formed by the printing plate and the doctor blade, the slower the moving speed of the doctor blade, and the more ink is pressed; the smaller the angle of the doctor blade, the better the ink is pressed out.
Smart cards are also called "integrated circuit cards", referred to as I C cards. It is made by encapsulating an integrated circuit chip module with storage, encryption and data processing capabilities in a plastic substrate. Smart cards can be divided into single-layer cards and multi-layer cards. Single-layer IC cards are produced by direct printing of single-layer PVC raw materials or by injection molding. Multi-layer I C cards can be divided into contact card, contactless card and combination card according to different structures and working modes.
1. Printing of smart cards
The printing of smart cards is basically the same as that of general magnetic cards. Currently, offset printing and screen printing are mainly used. Offset printing generally prints high-precision photos, patterns, etc., and can reproduce clear dots and very thin lines, with low plate making and printing costs, and clear text and images. The offset printing machine mainly has a special PVC card printing machine or an imported four-color printing machine. It mainly uses U V offset printing ink, and the printing color is bright and the graphic is clear, which is suitable for mass printing. It is printed on the P V C material first, then laminated, punched, magnetically written, embossed, etc., but the U V ink is used for offset printing, so that the protective film is easy to fall off. Therefore, a 2mm blank should be left around the plastic magnetic card during design. It is best not to use fluorescent ink. Pay attention to cutting or processing.
Screen printing has the characteristics of thick ink layer, good hiding power, rich texture, strong light resistance, bright colors, and good printability for inks and substrates. Therefore, screen printing is the main printing method for smart cards.
Smart card printing usually uses resin-based heat-curing inks and solvent-based soft-plastic screen printing inks. The selection of inks should mainly pay attention to the two factors of strong adhesion and high hiding power. This is also the key to the card printing. Adhesion mainly affects the adhesion of the ink to the card substrate, and the hiding power mainly affects the printing quality. Therefore, when adjusting the viscosity of the ink, it is necessary to select a solvent which is more compatible with the ink. When adjusting the ink, it is necessary to control the amount of solvent added. The solvent is too much, the viscosity of the ink is low, and it is easy to flow to the back of the screen, causing the printing pattern to become thicker and thicker; the solvent is too small, the viscosity of the ink is high, and the printing is easy to cause blocking. The net makes it difficult to completely reproduce the printed pattern. In addition, in the printing process, as the solvent evaporates, the viscosity of the ink will gradually increase. Therefore, it is necessary to pay attention to the ink on the screen often, and continuously adjust the ink to have a stable viscosity. The color of the ink should be based on the basic color, and the number of colors of the ink should be as small as possible. Generally, the color of the ink is 3 to 4 kinds. If you use too much ink, it will be more difficult to call out the ideal hue. In the blended ink, there are often a lot of bubbles. The ink with low viscosity will naturally defoam for a certain period of time; if the viscosity is high, it is necessary to add about 1% of antifoaming agent and stir well. The drying time of the ink is related to the size and characteristics of the IC card printing pattern. Generally, the full-page pattern has a long drying time, and the drying time of characters and small color blocks is slightly shorter. However, it should be noted that the freshly dried magnetic card is elongated due to the heat of the material, so it must be cooled (usually cooled for about 10 minutes) to print the next color. If the cold air can be blown to the printed matter, the effect is better. The quality of the screen production plays a key role in print quality. Because the domestic mesh is not ideal in terms of elongation and wear resistance, imported nylon mesh is often used. Screen printing generally selects 150-350 mesh screens, but for gold and silver ink printing, the size of all gold and silver powder particles should be considered when selecting the mesh number to ensure that it can pass through the mesh aperture. Usually 160 to 250 mesh is suitable. The frame of the net frame is made of aluminum alloy frame. The selection of the frame should pay attention to the flatness of the four sides and the distortion of the frame. When re-stretching the net with the old frame, use a grinding wheel to smooth the mesh frame. Pay attention to check the quality of the stretched screen, so that the tension of each set of screens and each of the four corners of the screen is consistent, and the tension is generally controlled at 14-15 N/cm. For the angle of the stretch net, except for some full-page patterns, the 90 ° straight stretch net can be used. Generally, the oblique pattern is used as much as possible to avoid the sawtooth shape of the edge of the magnetic card pattern, which improves the clarity and printing of the graphic. quality.
Practice has proved that the angle of the mesh is 22.5°. The scraper is preferably made of polyurethane, which has strong solvent resistance, good wear resistance and can withstand temperatures up to 90 °C. The scraper should be ground frequently. Make sure that the blade edge is normal for each print. The scraping angle, pressure, sharpness of the cutting edge and smoothness of the blade have a direct influence on the printing quality. In addition, the control of the scraping angle, printing pressure, hardness of the squeegee and printing speed of the squeegee will cause chromatic aberration. Failure, therefore, attention should be paid to accumulating experience and reasonable control during operation. Magnetic card printing is currently dominated by flat screen printing and drum screen printing. The flat screen printing machine is the earliest mechanized screen printing machine. It has a semi-automatic and fully automatic machine type. The biggest feature of the drum type screen printing machine is that the printing table is cylindrical. Compared with the flat printing machine, the drum type screen printing machine has a fast printing speed and good product quality. However, the requirements for operation and accuracy adjustment are higher. Regardless of the type of screen printer, it is important to adjust the screen distance. If the screen distance is small, the screen will not pop up in time after over-inking, which will cause the screen to be in surface contact with the substrate, which will easily cause ink to ooze, which makes it difficult to draw ink; the mesh distance is too large, and the screen is extended when embossing When it is excessive, it is not easy to recover and slack, which causes errors in printing size and layout, and has the greatest impact on overprinting, which may cause malfunctions such as overprinting. In addition, we must also pay attention to adjust and control the matching relationship between the mesh distance and the frame size, ink viscosity, and screen tension.
Since current screen printing cards generally only print simple text and graphics, high quality color patterns cannot be printed. Therefore, in order to produce a large-volume, high-quality magnetic card, the screen printing and the offset printing are usually used in combination, and the advantages of the two printing methods are taken to complement each other. Generally, the large-area colored portion is screen-printed, and the thin line or small-text portion is printed by a small offset printing machine to compensate for the shortage of screen printing. However, since the screen printing is printed by a flexible screen printing, and there is a reason that the tension of each screen may not be completely uniform, it is easy to cause a certain error between the screen printing magnetic card pattern size and the plate-making film size, thus, in the screen printing and In offset printing, there is a problem of registration errors. The solution to this problem is mainly to adjust the printing method. In general, you should try to print on the screen first, and then offset. In this way, the offset can be adjusted according to the actual size of the screen printing. When the size of the mouth and the tip are different, the longitudinal dimension of the offset image can be adjusted by adjusting the blanket of the offset printing machine, changing the thickness of the printing package, and the lateral dimension can be adjusted according to the actual size of the screen printing. . In this way, the registration problem of screen printing and offset printing is basically solved.
2. Anti-counterfeiting printing of smart cards
IC card as an important information media, the surface anti-counterfeiting treatment as an important part of the overall system release management needs to be carefully considered. The technical treatment of the surface of the card body is mainly color pattern printing. Most of the surface pattern printing of IC cards uses a lithographic offset printing process. The characteristics of the offset printing process on the plastic surface not only make the card artistically appealing and collectible, but more importantly, it greatly improves the precision, particularity and complexity of the production, and increases the difficulty and risk of forgery. Some simple monochrome patterns, text or anti-counterfeiting inks are also screen printed. In addition, special signs such as fluorescent security image printing, color-changing markings, laser-engraved signatures and images, micro-line techniques, complex holographic image markings, miniature borders, and security background structures can be used.
At present, color portrait PVC cards have been widely used. It can not only print different personalized photos, names and other personalized information on the card, but also change the previous functions of the plastic card, such as single function, easy to forge, easy to damage, easy to open glue, not waterproof, etc. It is solid, waterproof, with good image effect and versatile features, and can be used to identify attendance, access control, consumption and other functions in one. There are two kinds of PVC color portrait cards. One is to print directly on the surface of a blank card using a thermal transfer card printer, which is costly. The other is to print the content to a color inkjet or laser printer. On the special PVC film base, the finished product is produced by hot pressing, punching and punching by lamination method.
In order to improve the anti-counterfeiting effect of the IC card, there are now a multi-layer invisible photoelectric card, which is a significant improvement on the optical card with clear hole and the barcode card with clear code. The structure includes the card base, the connection coating, the information layer and the protective layer. , invisible layer and film. The card base is generally made of plastic materials such as PVC, ABS, PET, etc. The joint coating is generally made of PVC material. It is a special material that can firmly connect the information layer of the powder material with the card base material. And completely through. The information layer mainly uses carbon powder, and its optical properties have a great difference in infrared absorption compared with the card base material. The protective layer can be made of a thin PVC material to protect the information layer and the connecting coating from the invisible layer. The invisible layer can be used for materials having good infrared transmittance and low visible light transmittance, such as invisible inks, PVC films with deep color and infrared light transmission. Its function is to cover the area composed of information points under the invisible layer, so that it can not be discovered when visually, thus achieving the purpose of invisibility. The film can be used with a P V C film, which serves to protect the invisible layer from being exposed to the outermost layer, thereby improving the wear resistance of the card.
The multi-layer invisible photoelectric card can be printed with ordinary materials by using a common material, and the prepared information can be directly printed on the card base material by a laser printer. Finally, the multi-layer material is pressed into a card by a heat sealing lamination process to form an anti-counterfeit card. This card not only has hidden information layer, but also has good anti-counterfeiting effect by visually observing anti-counterfeiting information, and has the advantages of strong wear resistance, strong bending resistance, stable card reading, convenient manufacture and low cost.
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