Second, gravure printing gravure printing is a printing method with excellent levels of performance, corresponding to a variety of substrates, seamless image printing, printing quality stability and other advantages. In Europe and the United States, the development of publishing and printing with the aim of mass production as the main body has developed. In Japan, the use of package gravure as the center has become popular.
Packaging gravure is made of paper, cellophane, plastic, plastic film as printing material, printing quality is high, and a wide range of solvent types are used depending on the printing materials. Therefore, compared with cheap flexographic printing in Japan, the gravure of packaging has been widely used. universal. The Japan National Gravure Cooperative Syndicate Federation, consisting mainly of professional gravure printing companies, has 200 corporate members, most of whom are packaging gravure companies.
Gravure printing was heavily invested in environmental protection equipment such as printing machines and plate-making equipment, and the recovery of heart solvents. In Japan, there are about 60 publishing gravure printers that are mainly used by large companies. Its print level performance is unmatched by other printing methods.
(I) Publication of Gravure Printing Although there are single-sheet gravure printing machines used for printing art books in gravure printing, the mainstream of publishing gravure printing is high-speed web rotary gravure printing machines suitable for large-volume printing. From a global point of view, high-speed wide-format machines with high-volume and low-cost targets have made progress, with a maximum speed of 17 meters per second and a roll width of 2450-3480mm.
In Japan, although a 2,450mm wide device has been introduced, compared with Europe and the United States, Japan's publishing market is small and multi-variety and small-batch, so the mainstream width is 1900mm. Publication Gravure has begun to compete with offset printing. Existing problems include reducing costs, improving quality, and taking environmental measures.
1. Gravure Printing System The biggest feature of gravure printing machines is that they can produce a variety of sizes and number of folds by changing the diameter of the paper and plate cylinders. The gravure machines produced by Aruba (Germany) and Cerruti (Italy) occupy absolute market share. Japanese manufacturers such as Toshiba Machine and Japan Seiko are also producing.
Paper feeding department. Since it is a high-speed printing, a high-speed gluing and splicing device that is synchronized with the rotation speed of the paper roll is generally used.
Crew department. The gravure printing is to physically transfer the ink filled in the concave part of the plate cylinder to the substrate, and each color should be dried (mainly using hot air drying). A variety of inks can be used and printed on a variety of substrates. The gravure printing uses a simple direct printing method, so the stability is good and the printing quality is consistent. Due to the long paper path, tension control and print registration become difficult.
Folding machine. Folding machines are models with adjustable size and number of pages. Unlike an offset press, the diameter of the plate cylinder is variable, and the folding machine accordingly also changes the folding size. The printed tape is cut into narrow tapes. By changing the position of the knife, the size of the print head can be changed. The size of the cut direction is changed by changing the position of the fold by changing the phase of the teeth and the folding knife on the folding roller. At this time, the phase of the cutting roller is changed so that the folding machine can fold out the signatures that are afraid of the specifications.
2. Environmental protection equipment solvent recovery device: The use of activated carbon absorption of solvent gas recovery equipment. Toluene solvents must not be discharged outside and must be 100% recycled. The device will reuse the recovered solvent to reduce the cost of using the solvent.
3. As with offset printing, the control of temperature and humidity is very important for the gravure shop environment. In particular, when the temperature and humidity change drastically, it will inevitably have a great impact on the printing register. From a solvent concentration point of view, gravure room ventilation management is a must. Solvent recovery equipment can be used to limit solvent gas emissions near the unit. Considering the exhaust gas volume and the amount of air supply including the air conditioner, it is necessary to design the entire plant to prevent the accumulation of solvent gas.
4. Auxiliary Equipment For today's high-speed gravure printers, the following auxiliary equipment is indispensable: 1 Overprint control device. Without it, the current gravure printing cannot be carried out. 2 ink viscosity control device. Measure ink viscosity, adjust the amount of solvent added, and automatically adjust the viscosity of the device. 3 electrostatic printing device. Devices that use static electricity to help transfer ink. It is essential for engraving gravure and high-speed gravure. 4 quality inspection device. Now the quality requirements have increased, and even the products printed on the web have to be checked one by one. Current inspection devices cannot detect the problem of squeegee marks and need to be developed.
5. Ink publishing Gravure, like offset printing, also uses four-color inks for printing. A great difference from offset printing is the use of low-viscosity toluene solvent inks, so gravure does not suffer from problems such as offset printing due to the high viscosity of the ink leading to breakage of the paper. Due to the use of low-boiling solvents under high-speed drying conditions, high-priced solvent recovery devices and explosion-proof devices need to be used. The disadvantage of the commonly used gravure inks is the use of organic solvents. The water-based and non-toluene-free inks are important for both gravure printing and gravure printing. However, gravure printing uses only toluene solvent, and its recovery technology has been established. It has been widely used in gravure printing plants. Evaporated solvent is recycled. In order to recover completely, it is necessary to prevent the discharge of solvent gas outside the workshop and it must be prevented from leaking to the workplace. Therefore, a countermeasure for completely sealing off the part using the solvent and achieving complete recovery of the solvent is being put forward. The biggest remaining problem is to reduce costs.
6. Future developments The future development is mainly determined by the publishing market and the postal advertising market. For gravure printing of high-volume products, it can play its specialty, but from the status quo in Japan, it cannot be considered that the market will generally expand. Therefore, when gravure printing competes with offset printing for the market, it should aim at fully reducing costs, so that prints can achieve rich levels of performance and high contrast.
(2) Packaging Gravure Printing 1990-1995. Along with the development of the packaging field, the packaging gravure printing machine and its related technologies, which are suitable for large-volume printing and have good printing processability, have achieved rapid development. Due to changes in the economic situation in recent years, the pursuit of diversification of products, small batches, short delivery, high quality, and low prices, the old set of technologies can no longer meet these requirements.
For packaging gravure, packaging materials are used to make bags or boxes, and bags or boxes are not sized. The basic size of the package is determined according to the size, quantity, etc. of the contents, and in particular, the circumference and the length of the heart roller of the plate cylinder are determined according to the layout connection requirements. The composition of the packaging material is determined according to the contents, and the shape of the packaging is determined according to the specifications of the filler and the packaging machine of the caregiver. Substrate materials have a variety of plastic film, cardboard and so on. The inks used are also varied depending on the printability of the paper (plastic film), especially for food packaging. The reason is that the reason for the deterioration of the contents of different contents in the packaging is complicated, so there are numerous packaging materials and inks used. The package gravure produces the packaged product via the process shown in FIG.
1. The unwinding and take-up section is mainly used for the rotation of the double paper shaft, and there are also three paper shafts for rotation. If the axes of the double-shaft rotation device are the A-axis and the B-axis respectively, when the A-axis is unwinding, the paper core on the B-axis is removed, the new paper roll is loaded and rotated back, and the high-speed cutter is used to complete the old and new. Paper tape bonding. The installation of the paper roll is accomplished by pneumatic shafts and pneumatic clamping devices. The unwinding process is the opposite. In addition, a new high-speed cutting and rolling device aimed at reducing broke has recently been introduced. This modified type is not a laser cutting device with an energy storage device (a high price, occupying a floor). Instead, the device is used to completely wrap the tape cuts on the paper core, thereby reducing wrinkle damage caused by unwinding. Compared with the conventional devices, not only the speed is high but also the speed of the paper is cut faster than the speed of the paper strip. In particular, the tape is pressed onto the paper core by a brush, so that the paper strip is well wrapped on the paper core. on.
2. Plate cylinder As mentioned above, after the packaging specification is confirmed, the plate cylinder size is determined. Recently, due to the opinion that the size of the roller is too large, companies are beginning to reduce it to a number of sizes. Basically speaking, the drum will be kept until the revision, so the saved version of the drum is not a small number. In addition, since it is necessary to store a large number of plate cylinders, in terms of flexible package printing, people do not like the high-cost, land-use plate cylinders, and more use of shaftless cylinders. For large machines such as printed cardboard, the use of large drums such as gravure printing, the use of a shaft version of the drum is often used for ease of installation.
3. The printing unit feeding device includes a dip coating method for directly applying the ink of the ink tank to the plate cylinder, an ink supply roller for transferring the ink of the ink tank to the ink roller of the plate cylinder, and the like. The method of applying the ink roller to the highlight section has recently been adopted more. Ink roller mode also reduces residual ink.
Platen installation. Due to the use of shaftless rollers, pneumatic clamping can be used. Since the platen cylinder rolls with a rubber layer, no drive is required. To prevent the solvent from damaging the rubber, it has been the past practice to match the width of the impression cylinder rubber with the width of the substrate. In order to quickly correspond to the size of the printing material, a rotatable device is built in the unit, and 2-3 impression cylinders are built in. However, due to the improvement of rubber properties in recent years, as long as a wide impression cylinder is used, it can correspond to various widths of substrates.
Due to the small printing tension in flexible packaging, the drying oven adopts a roller bracket structure. Plastic film exits the oven through the chill roll into the next color group.
Double-sided printing is achieved by a flipping mechanism or the like. After packaging the goods in a flexible package, they can only see the printed side of the package. It is rare to see double-sided printed products. The printed content on the back is mostly monochromatic or monochromatic text for observation.
4. The control of the gravure press has been one of the fastest growing gravure printing machines in recent years. About 10 years ago, DC motors were used for speed control, and powder brakes, disk brakes, etc. were used for brakes. Now, AC vector motors are used, which greatly improves the tension control technology. Small tension printing, which was impossible in the past, is now available, and printing of easily stretchable plastic films such as polyethylene has also become simple. Recently, a segment-driven gravure printer with a servo motor has also been introduced.
5. Gravure inks have very low viscosity compared to offset inks. Because of the use of a highly volatile solvent, it dries quickly, but the concentration of the ink easily changes. In order to obtain a stable printing, it is necessary to control the ink viscosity and the like.
India. For plastic film printing, in-print printing is used to brighten the surface and protect the ink. Compared with the printing of paper, the printed color sequence is reversed and the plate-making image is reversed. The printed color sequence in India is black → blue → magenta → yellow. If it is a paper-and-plastic machine, then when the paper is changed from printing paper to printing film, all the units must change color. In addition, a positive image is seen on the plate cylinder printed in the plastic film.
Spot color. Compared with gravure printing, gravure packing has more real land masses, and it is not easy to reproduce spot colors with four colors. Therefore, spot colors are often used for printing.
Automatic register device. The distance between the printing materials in the package gravure printing machine and the drying time between the printing units is very long, and it is easy to cause tension change and expansion and contraction change. Generally, an automatic register device is installed to read the overprint marks on the printing products by the scanning head. When overprinting occurs, the registration roller is adjusted by adjusting the compensation roller between the units.
Image checker. Can automatically detect print online failures and notify the operator. In particular, the problematic part can be tagged to alert the next process. Some recent devices can use the camera to detect problematic parts and display or print them out.
The preset system can easily reproduce the last printing condition when the printing instruction is issued again based on the data stored in the previous printing. The set items include: 1 printing pressure; 2 blade pressure; 3 blade position; 4 printing speed; 5 compensation roller position; 6 drying temperature.
Viscosity control measures the speed of the impeller in the ink or detects changes in viscosity based on the action of a pneumatic diaphragm pump and automatically replenish the solvent. ("Printing World")
Packaging gravure is made of paper, cellophane, plastic, plastic film as printing material, printing quality is high, and a wide range of solvent types are used depending on the printing materials. Therefore, compared with cheap flexographic printing in Japan, the gravure of packaging has been widely used. universal. The Japan National Gravure Cooperative Syndicate Federation, consisting mainly of professional gravure printing companies, has 200 corporate members, most of whom are packaging gravure companies.
Gravure printing was heavily invested in environmental protection equipment such as printing machines and plate-making equipment, and the recovery of heart solvents. In Japan, there are about 60 publishing gravure printers that are mainly used by large companies. Its print level performance is unmatched by other printing methods.
(I) Publication of Gravure Printing Although there are single-sheet gravure printing machines used for printing art books in gravure printing, the mainstream of publishing gravure printing is high-speed web rotary gravure printing machines suitable for large-volume printing. From a global point of view, high-speed wide-format machines with high-volume and low-cost targets have made progress, with a maximum speed of 17 meters per second and a roll width of 2450-3480mm.
In Japan, although a 2,450mm wide device has been introduced, compared with Europe and the United States, Japan's publishing market is small and multi-variety and small-batch, so the mainstream width is 1900mm. Publication Gravure has begun to compete with offset printing. Existing problems include reducing costs, improving quality, and taking environmental measures.
1. Gravure Printing System The biggest feature of gravure printing machines is that they can produce a variety of sizes and number of folds by changing the diameter of the paper and plate cylinders. The gravure machines produced by Aruba (Germany) and Cerruti (Italy) occupy absolute market share. Japanese manufacturers such as Toshiba Machine and Japan Seiko are also producing.
Paper feeding department. Since it is a high-speed printing, a high-speed gluing and splicing device that is synchronized with the rotation speed of the paper roll is generally used.
Crew department. The gravure printing is to physically transfer the ink filled in the concave part of the plate cylinder to the substrate, and each color should be dried (mainly using hot air drying). A variety of inks can be used and printed on a variety of substrates. The gravure printing uses a simple direct printing method, so the stability is good and the printing quality is consistent. Due to the long paper path, tension control and print registration become difficult.
Folding machine. Folding machines are models with adjustable size and number of pages. Unlike an offset press, the diameter of the plate cylinder is variable, and the folding machine accordingly also changes the folding size. The printed tape is cut into narrow tapes. By changing the position of the knife, the size of the print head can be changed. The size of the cut direction is changed by changing the position of the fold by changing the phase of the teeth and the folding knife on the folding roller. At this time, the phase of the cutting roller is changed so that the folding machine can fold out the signatures that are afraid of the specifications.
2. Environmental protection equipment solvent recovery device: The use of activated carbon absorption of solvent gas recovery equipment. Toluene solvents must not be discharged outside and must be 100% recycled. The device will reuse the recovered solvent to reduce the cost of using the solvent.
3. As with offset printing, the control of temperature and humidity is very important for the gravure shop environment. In particular, when the temperature and humidity change drastically, it will inevitably have a great impact on the printing register. From a solvent concentration point of view, gravure room ventilation management is a must. Solvent recovery equipment can be used to limit solvent gas emissions near the unit. Considering the exhaust gas volume and the amount of air supply including the air conditioner, it is necessary to design the entire plant to prevent the accumulation of solvent gas.
4. Auxiliary Equipment For today's high-speed gravure printers, the following auxiliary equipment is indispensable: 1 Overprint control device. Without it, the current gravure printing cannot be carried out. 2 ink viscosity control device. Measure ink viscosity, adjust the amount of solvent added, and automatically adjust the viscosity of the device. 3 electrostatic printing device. Devices that use static electricity to help transfer ink. It is essential for engraving gravure and high-speed gravure. 4 quality inspection device. Now the quality requirements have increased, and even the products printed on the web have to be checked one by one. Current inspection devices cannot detect the problem of squeegee marks and need to be developed.
5. Ink publishing Gravure, like offset printing, also uses four-color inks for printing. A great difference from offset printing is the use of low-viscosity toluene solvent inks, so gravure does not suffer from problems such as offset printing due to the high viscosity of the ink leading to breakage of the paper. Due to the use of low-boiling solvents under high-speed drying conditions, high-priced solvent recovery devices and explosion-proof devices need to be used. The disadvantage of the commonly used gravure inks is the use of organic solvents. The water-based and non-toluene-free inks are important for both gravure printing and gravure printing. However, gravure printing uses only toluene solvent, and its recovery technology has been established. It has been widely used in gravure printing plants. Evaporated solvent is recycled. In order to recover completely, it is necessary to prevent the discharge of solvent gas outside the workshop and it must be prevented from leaking to the workplace. Therefore, a countermeasure for completely sealing off the part using the solvent and achieving complete recovery of the solvent is being put forward. The biggest remaining problem is to reduce costs.
6. Future developments The future development is mainly determined by the publishing market and the postal advertising market. For gravure printing of high-volume products, it can play its specialty, but from the status quo in Japan, it cannot be considered that the market will generally expand. Therefore, when gravure printing competes with offset printing for the market, it should aim at fully reducing costs, so that prints can achieve rich levels of performance and high contrast.
(2) Packaging Gravure Printing 1990-1995. Along with the development of the packaging field, the packaging gravure printing machine and its related technologies, which are suitable for large-volume printing and have good printing processability, have achieved rapid development. Due to changes in the economic situation in recent years, the pursuit of diversification of products, small batches, short delivery, high quality, and low prices, the old set of technologies can no longer meet these requirements.
For packaging gravure, packaging materials are used to make bags or boxes, and bags or boxes are not sized. The basic size of the package is determined according to the size, quantity, etc. of the contents, and in particular, the circumference and the length of the heart roller of the plate cylinder are determined according to the layout connection requirements. The composition of the packaging material is determined according to the contents, and the shape of the packaging is determined according to the specifications of the filler and the packaging machine of the caregiver. Substrate materials have a variety of plastic film, cardboard and so on. The inks used are also varied depending on the printability of the paper (plastic film), especially for food packaging. The reason is that the reason for the deterioration of the contents of different contents in the packaging is complicated, so there are numerous packaging materials and inks used. The package gravure produces the packaged product via the process shown in FIG.
1. The unwinding and take-up section is mainly used for the rotation of the double paper shaft, and there are also three paper shafts for rotation. If the axes of the double-shaft rotation device are the A-axis and the B-axis respectively, when the A-axis is unwinding, the paper core on the B-axis is removed, the new paper roll is loaded and rotated back, and the high-speed cutter is used to complete the old and new. Paper tape bonding. The installation of the paper roll is accomplished by pneumatic shafts and pneumatic clamping devices. The unwinding process is the opposite. In addition, a new high-speed cutting and rolling device aimed at reducing broke has recently been introduced. This modified type is not a laser cutting device with an energy storage device (a high price, occupying a floor). Instead, the device is used to completely wrap the tape cuts on the paper core, thereby reducing wrinkle damage caused by unwinding. Compared with the conventional devices, not only the speed is high but also the speed of the paper is cut faster than the speed of the paper strip. In particular, the tape is pressed onto the paper core by a brush, so that the paper strip is well wrapped on the paper core. on.
2. Plate cylinder As mentioned above, after the packaging specification is confirmed, the plate cylinder size is determined. Recently, due to the opinion that the size of the roller is too large, companies are beginning to reduce it to a number of sizes. Basically speaking, the drum will be kept until the revision, so the saved version of the drum is not a small number. In addition, since it is necessary to store a large number of plate cylinders, in terms of flexible package printing, people do not like the high-cost, land-use plate cylinders, and more use of shaftless cylinders. For large machines such as printed cardboard, the use of large drums such as gravure printing, the use of a shaft version of the drum is often used for ease of installation.
3. The printing unit feeding device includes a dip coating method for directly applying the ink of the ink tank to the plate cylinder, an ink supply roller for transferring the ink of the ink tank to the ink roller of the plate cylinder, and the like. The method of applying the ink roller to the highlight section has recently been adopted more. Ink roller mode also reduces residual ink.
Platen installation. Due to the use of shaftless rollers, pneumatic clamping can be used. Since the platen cylinder rolls with a rubber layer, no drive is required. To prevent the solvent from damaging the rubber, it has been the past practice to match the width of the impression cylinder rubber with the width of the substrate. In order to quickly correspond to the size of the printing material, a rotatable device is built in the unit, and 2-3 impression cylinders are built in. However, due to the improvement of rubber properties in recent years, as long as a wide impression cylinder is used, it can correspond to various widths of substrates.
Due to the small printing tension in flexible packaging, the drying oven adopts a roller bracket structure. Plastic film exits the oven through the chill roll into the next color group.
Double-sided printing is achieved by a flipping mechanism or the like. After packaging the goods in a flexible package, they can only see the printed side of the package. It is rare to see double-sided printed products. The printed content on the back is mostly monochromatic or monochromatic text for observation.
4. The control of the gravure press has been one of the fastest growing gravure printing machines in recent years. About 10 years ago, DC motors were used for speed control, and powder brakes, disk brakes, etc. were used for brakes. Now, AC vector motors are used, which greatly improves the tension control technology. Small tension printing, which was impossible in the past, is now available, and printing of easily stretchable plastic films such as polyethylene has also become simple. Recently, a segment-driven gravure printer with a servo motor has also been introduced.
5. Gravure inks have very low viscosity compared to offset inks. Because of the use of a highly volatile solvent, it dries quickly, but the concentration of the ink easily changes. In order to obtain a stable printing, it is necessary to control the ink viscosity and the like.
India. For plastic film printing, in-print printing is used to brighten the surface and protect the ink. Compared with the printing of paper, the printed color sequence is reversed and the plate-making image is reversed. The printed color sequence in India is black → blue → magenta → yellow. If it is a paper-and-plastic machine, then when the paper is changed from printing paper to printing film, all the units must change color. In addition, a positive image is seen on the plate cylinder printed in the plastic film.
Spot color. Compared with gravure printing, gravure packing has more real land masses, and it is not easy to reproduce spot colors with four colors. Therefore, spot colors are often used for printing.
Automatic register device. The distance between the printing materials in the package gravure printing machine and the drying time between the printing units is very long, and it is easy to cause tension change and expansion and contraction change. Generally, an automatic register device is installed to read the overprint marks on the printing products by the scanning head. When overprinting occurs, the registration roller is adjusted by adjusting the compensation roller between the units.
Image checker. Can automatically detect print online failures and notify the operator. In particular, the problematic part can be tagged to alert the next process. Some recent devices can use the camera to detect problematic parts and display or print them out.
The preset system can easily reproduce the last printing condition when the printing instruction is issued again based on the data stored in the previous printing. The set items include: 1 printing pressure; 2 blade pressure; 3 blade position; 4 printing speed; 5 compensation roller position; 6 drying temperature.
Viscosity control measures the speed of the impeller in the ink or detects changes in viscosity based on the action of a pneumatic diaphragm pump and automatically replenish the solvent. ("Printing World")
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