In the packaging and printing process, there are often different materials used to print the same or similar layout, such as internal and external packaging products, trademarks, brochures and other series of printed products, the general color layout of the printed text or logo are basically the same, but due to The difference in the characteristics of the substrate, some products used in the printing equipment, ink properties and process forms are not necessarily the same, and customers often require that the color printing products of a series of products basically the same, can not appear obvious color difference. The actual production process shows that there are certain difficulties in the control of the quality of the ink of different series of printed materials. It is necessary to carefully control the design and operation of the technology in order to obtain good printing quality and meet the quality requirements of customers.
First, the characteristics of the series of print analysis and process determination
The so-called series of prints means that the same type of product has different specifications for the internal and external packages, or the printed materials used in the set of products are not the same, but the graphic layout or color is the same or similar. Due to differences in material properties or printing layout specifications, the adaptability of the printing process is also very different. For example, corrugated cartons on the outside of the box, color box surface layer printing materials include whiteboard, leather or cardboard, and the carton packaging materials include whiteboard, leather, white card, glass card, copper plate, PE coated paper. And so on, flexible packaging plastic film, cellophane, tissue paper, glossy paper, copy paper, offset paper, vacuum aluminum paper, laser paper and so on. Corrugated board thickness, surface flatness characteristics, and PE coated paper, plastic film, cellophane, tissue paper, vacuum aluminized paper printing process, from the material characteristics and product packaging safety, hygienic quality considerations, suitable for flexible version Printing with water-based ink can better ensure product quality. For the pre-printing process color box paper, color box printing white paper, leather card; vacuum aluminum paper, laser paper and other materials, a large number of gravure or flexographic technology can be used to enable printing quality and production costs are Better balance. As for the whiteboard paper, leather card, white card, glass card, and copperplate card products with a quantity of about 100,000 sheets, and glossy paper, copy paper, offset paper, vacuum aluminum-plated paper, and laser paper, the offset printing process may be more appropriate. Among them, the glossy paper and copy paper have lower quantification and are not suitable for high-speed automatic paper feeding. A low-speed 01 offset press can be used for printing to better ensure the quality of overprinting of products.
Second, we must pay attention to the pre-press layout design process technology control
Nowadays, many printed materials are provided by customers with electronic manuscripts designed or produced by their own design or advertising company. Due to their incomplete understanding of the printing process, they often result in manuscripts that are produced and cannot be adapted to the requirements of the printing process. Taking the series of prints with the same textured structure as an example, since the printed materials used are not the same, the printing colors will be greatly different. It is the same type of paper plate (white paper material) and paper cup (single-sided PE coated paper) that are also printed by the offset printing process. Because the surface smoothness of the white paper material is good, the amount of ink absorption is small, and the single-sided PE coating film The surface of the paper is relatively rough, and the amount of ink suction is larger. Using the same material for printing the same structure of the textured structure, the color will vary greatly. Generally, the printing color of the single-sided PE coated paper is obviously lighter than the white paper. The amount of ink and pressure adjustment often cannot overcome the problem of color aberration that occurs due to the difference in the printing performance of the material. Generally, the main color dot area of ​​the printed single-sided PE coated paper should be properly adjusted to a larger size through the plate design so that the printing color can be brought close to the value. Therefore, when receiving a series of prints with the same structure of the texture pattern and different printing materials, it is necessary to carefully analyze the structure of the original layout and the characteristics of the material of the printing material, and then determine a reasonable design scheme for the pattern, that is, according to Material gloss, printing ink-absorbing performance, reasonable adjustment of the dot area of ​​a certain product layout, to ensure that the different materials printed by the color are close to each other.
Third, we must pay attention to the direction of the process technology control
Multi-fighted structure of the printed matter, a printed sheet is usually spelled several different varieties of layout, if you do not take into account the differences in the color printing of different species, but the different colors of different varieties in the same vertical, then, once the vertical layout of which When a certain layout printing color appears dark or dark, it is difficult to locally adjust the ink output through the ink fountain to realize the ink control of a certain type of layout of the corresponding vertical layout. The ink adjustment tends to result in a situation of misunderstanding, and there is no way to Take into account the printing color of the vertical overall layout.
Therefore, for multi-stitched paper plates, paper cups, trademarks, and other products, each vertical position is best to spell the same species or spell color close to the species, in order to facilitate the effective adjustment of the amount of ink coating. Do not fight in the same longitudinal position a few products with a large contrast of colors, because such imposition will be the most likely to produce color, even if the ability to control the printing color through the adjustment of the ink coating amount, but it is easy to produce chain printing quality problems, such as Pull paper, paste, dirty version and other bad conditions.
Fourth, adjust the control network size through the printing process
The main features of a series of prints are generally the same graphics and text, but the difference in size, and the material properties of the substrate are completely different. If the film texture structure has been produced is the same, it can be considered in the printing process technology, according to the glossiness and ink absorption of the substrate, properly control the exposure time of the main color version of a certain product. Realize the adjustment of the dot size. For example, there are two types of substrates: glass cards and offset papers. The offset paper layout is relatively rough and the amount of ink is large. The exposure time of the main color version can be shortened to increase the dot area. The ink color of the offset printing paper can come close to the ink color of the glass card printing plate layout, and it is not prone to the problems of pasting. However, it must be pointed out that there is a limit to the size of outlets that can be adjusted in the printing process, and only minor adjustments can be made. If the exposure time is too short, the layout is prone to dullness, and the leveling of the layout is poor. Therefore, the exposure time adjustment to grasp a suitable degree, such as the original normal exposure should be 140S, the shortened exposure time to control the 110s ~ 120s appropriate.
Fifth, control printing color by adjusting printing pressure
Printing pressure is the medium of imprint transfer. The pressure of printing directly reflects the depth of printing ink, especially the letterpress printing process. The pressure has a greater influence on the depth of printing ink. When the printing pressure increases, the printing color will appear. Deepen the phenomenon, on the contrary, reduce the printing pressure, the printing color will appear shallow. For a series of printed matter of different substrates, when the surface of the printed material is rough, the printing pressure may be appropriately increased to deepen the printing color, so that the color of printed matter of different materials can be brought close to each other. However, the adjustment of printing pressure must also be controlled to an appropriate degree. Excessive pressure adjustment can easily speed up the wear of the printing plate, and it can easily produce chain quality problems such as stencil printing and large-scale deformation of the printing plate surface. This is a problem to be paid attention to during the printing process operation. . General letterpress printing pressure increase adjustment, not more than 30 wire, otherwise, printing distortion will directly affect the product's overprint quality.
Sixth, through the ink hue adjustment control printing color
Four-color prints are printed using standard four-color inks according to the conventional process. However, when a certain color color is found to be inconsistent, and the ink volume adjustment cannot meet the color requirements, the hue of a certain color ink may be considered. Appropriate adjustments make the ink color of the printed product conform to the original color. For example, when we printed a four-color logo, there was a clear reddish phase in the color of the superficially bright orange after superimposition, and the yellow hue had a clear lack of sensation, a large difference from the original color, and a decrease in the amount of M color ink. The increase in Y color is limited, and cannot be adjusted to the same requirement as the original ink. In this case, it seems that only by appropriately reducing the dot area of ​​the M version and increasing the dot area of ​​the Y version can the effect be achieved. Adjusting the effect of color, however, it is very time consuming and will increase economic costs, which is undesirable. The author through careful analysis and study of the printing sample, found that the entire layout of the Y-color part of the flat screen and the M color version of the flat network there is an overprint relationship, the M color version does not have a single color rendering results, so , The author germinated in the 'four-color red' ink, adding some 'four-color yellow' ink, the composition of a special spot color red ink overprint, through this treatment, light orange overlay printing layout, printing color instantly A similar effect to the color of the sample is achieved, so that the printing color of the product finally meets the requirements of the customer. In the same way, in printing a series of printed materials of different materials, the hue of a certain main color often appears to be significantly lighter due to the difference in the materials. In this regard, appropriate adjustment of the hue of a certain ink may be considered to realize the printing ink color. This is the easiest and quickest way to correct it.
Seven, use different printing process features to control the printing color
Due to the difference in the printing process, the thickness of the printed ink layer is also significantly different. For a series of prints with large differences in material, according to the print layout color and the adaptability of the material to the printing process, a suitable process is selected for printing, which also controls the printing color. An effective way. The ink layer thickness of various printing processes is approximately: Offset 3μm; Embossing 8μm; Flexoprint 10μm; Gravureprint 12μm; Screenprint 30μm, according to the basic properties of the substrate, surface gloss, ink absorption, and layout pattern In the case of structures, etc., consider selecting printing processes suitable for the ink-absorbing properties of the substrate material, as appropriate. The offset printing process is limited by the balance of ink and ink. The adjustment range of the ink coating amount is small, and it is more suitable for printing substrates with relatively good glossiness, such as coated paper, glass card, white card, offset paper, whiteboard paper, and leather card. The napkin has a soft texture, a large ink absorption, a poor tensile strength, and is easily stretched and deformed. Therefore, the napkin is more suitable for printing with a low-viscosity liquid water-based ink to obtain an ideal printing color, and the water-based ink has a huge advantage in environmental protection. Therefore, using a flexo process to print napkins is the best choice. Choosing the printing process should not only consider the influence of the print characteristics of the substrate on the printing color, but also consider the printing production cost. For example, the gravure and flexographic plate making process is expensive and is more suitable for printing long-line products.
Eight, different material series print quality control methods
Due to limitations in the scale of production of a printing plant, for example, a factory has only a single flexo printing process, and some factories have a single offset or gravure printing process. Many series of printed products are often sent to several factories for printing. . Due to the cost of production, some customers did not use the proofing process, which is often a printed material of a certain kind of material printed before, as a color reference of another kind of material print, such as the use of printed soft-printed napkins as offset whiteboard paper. A control sample of the printing color of a paper or laminating paper cup brings certain difficulties to the control of the printing color, and the offset printing is often difficult to keep up with the flexo ink. Because the flexographic ink layer is thick, the offset ink layer can be adjusted to a smaller extent than the flexographic process. Therefore, when printing a series of printed matter using different techniques, it is advisable to arrange the printing of the product using the offset printing process and the use of flexo printing, gravure printing, or post-printing of silk screen printing. This is beneficial to the control of the color of a series of printed matters. If the same offset printing process is used to print products with different materials, it is considered that the materials with good glossiness should be printed first, and the materials with poor glossiness should be arranged after printing. Because of the good glossiness of the material, the control of the amount of printing ink is relatively accurate, which reduces the chance of a large deviation in the printing color. It is worth mentioning that the use of printed manuscripts as a reference for printing color should pay attention to the effect of the light transmission performance of sample materials on the identification of color vision. For instance, the transparency of film prints and napkin prints should be high, and they should be placed on the standard side with printed samples. Table for identification.
In summary, to control the color of a series of printed materials of different materials, it is necessary to pay attention to the comprehensive consideration of the characteristics of materials, printing process technology and equipment operation adjustment, and through careful technical analysis of the manuscript, and then determine the appropriate production process plan. Not only can avoid the blindness of the production process, reduce the occurrence of printing defects, but also can better guarantee the product's printing quality, and effectively improve the production efficiency.
First, the characteristics of the series of print analysis and process determination
The so-called series of prints means that the same type of product has different specifications for the internal and external packages, or the printed materials used in the set of products are not the same, but the graphic layout or color is the same or similar. Due to differences in material properties or printing layout specifications, the adaptability of the printing process is also very different. For example, corrugated cartons on the outside of the box, color box surface layer printing materials include whiteboard, leather or cardboard, and the carton packaging materials include whiteboard, leather, white card, glass card, copper plate, PE coated paper. And so on, flexible packaging plastic film, cellophane, tissue paper, glossy paper, copy paper, offset paper, vacuum aluminum paper, laser paper and so on. Corrugated board thickness, surface flatness characteristics, and PE coated paper, plastic film, cellophane, tissue paper, vacuum aluminized paper printing process, from the material characteristics and product packaging safety, hygienic quality considerations, suitable for flexible version Printing with water-based ink can better ensure product quality. For the pre-printing process color box paper, color box printing white paper, leather card; vacuum aluminum paper, laser paper and other materials, a large number of gravure or flexographic technology can be used to enable printing quality and production costs are Better balance. As for the whiteboard paper, leather card, white card, glass card, and copperplate card products with a quantity of about 100,000 sheets, and glossy paper, copy paper, offset paper, vacuum aluminum-plated paper, and laser paper, the offset printing process may be more appropriate. Among them, the glossy paper and copy paper have lower quantification and are not suitable for high-speed automatic paper feeding. A low-speed 01 offset press can be used for printing to better ensure the quality of overprinting of products.
Second, we must pay attention to the pre-press layout design process technology control
Nowadays, many printed materials are provided by customers with electronic manuscripts designed or produced by their own design or advertising company. Due to their incomplete understanding of the printing process, they often result in manuscripts that are produced and cannot be adapted to the requirements of the printing process. Taking the series of prints with the same textured structure as an example, since the printed materials used are not the same, the printing colors will be greatly different. It is the same type of paper plate (white paper material) and paper cup (single-sided PE coated paper) that are also printed by the offset printing process. Because the surface smoothness of the white paper material is good, the amount of ink absorption is small, and the single-sided PE coating film The surface of the paper is relatively rough, and the amount of ink suction is larger. Using the same material for printing the same structure of the textured structure, the color will vary greatly. Generally, the printing color of the single-sided PE coated paper is obviously lighter than the white paper. The amount of ink and pressure adjustment often cannot overcome the problem of color aberration that occurs due to the difference in the printing performance of the material. Generally, the main color dot area of ​​the printed single-sided PE coated paper should be properly adjusted to a larger size through the plate design so that the printing color can be brought close to the value. Therefore, when receiving a series of prints with the same structure of the texture pattern and different printing materials, it is necessary to carefully analyze the structure of the original layout and the characteristics of the material of the printing material, and then determine a reasonable design scheme for the pattern, that is, according to Material gloss, printing ink-absorbing performance, reasonable adjustment of the dot area of ​​a certain product layout, to ensure that the different materials printed by the color are close to each other.
Third, we must pay attention to the direction of the process technology control
Multi-fighted structure of the printed matter, a printed sheet is usually spelled several different varieties of layout, if you do not take into account the differences in the color printing of different species, but the different colors of different varieties in the same vertical, then, once the vertical layout of which When a certain layout printing color appears dark or dark, it is difficult to locally adjust the ink output through the ink fountain to realize the ink control of a certain type of layout of the corresponding vertical layout. The ink adjustment tends to result in a situation of misunderstanding, and there is no way to Take into account the printing color of the vertical overall layout.
Therefore, for multi-stitched paper plates, paper cups, trademarks, and other products, each vertical position is best to spell the same species or spell color close to the species, in order to facilitate the effective adjustment of the amount of ink coating. Do not fight in the same longitudinal position a few products with a large contrast of colors, because such imposition will be the most likely to produce color, even if the ability to control the printing color through the adjustment of the ink coating amount, but it is easy to produce chain printing quality problems, such as Pull paper, paste, dirty version and other bad conditions.
Fourth, adjust the control network size through the printing process
The main features of a series of prints are generally the same graphics and text, but the difference in size, and the material properties of the substrate are completely different. If the film texture structure has been produced is the same, it can be considered in the printing process technology, according to the glossiness and ink absorption of the substrate, properly control the exposure time of the main color version of a certain product. Realize the adjustment of the dot size. For example, there are two types of substrates: glass cards and offset papers. The offset paper layout is relatively rough and the amount of ink is large. The exposure time of the main color version can be shortened to increase the dot area. The ink color of the offset printing paper can come close to the ink color of the glass card printing plate layout, and it is not prone to the problems of pasting. However, it must be pointed out that there is a limit to the size of outlets that can be adjusted in the printing process, and only minor adjustments can be made. If the exposure time is too short, the layout is prone to dullness, and the leveling of the layout is poor. Therefore, the exposure time adjustment to grasp a suitable degree, such as the original normal exposure should be 140S, the shortened exposure time to control the 110s ~ 120s appropriate.
Fifth, control printing color by adjusting printing pressure
Printing pressure is the medium of imprint transfer. The pressure of printing directly reflects the depth of printing ink, especially the letterpress printing process. The pressure has a greater influence on the depth of printing ink. When the printing pressure increases, the printing color will appear. Deepen the phenomenon, on the contrary, reduce the printing pressure, the printing color will appear shallow. For a series of printed matter of different substrates, when the surface of the printed material is rough, the printing pressure may be appropriately increased to deepen the printing color, so that the color of printed matter of different materials can be brought close to each other. However, the adjustment of printing pressure must also be controlled to an appropriate degree. Excessive pressure adjustment can easily speed up the wear of the printing plate, and it can easily produce chain quality problems such as stencil printing and large-scale deformation of the printing plate surface. This is a problem to be paid attention to during the printing process operation. . General letterpress printing pressure increase adjustment, not more than 30 wire, otherwise, printing distortion will directly affect the product's overprint quality.
Sixth, through the ink hue adjustment control printing color
Four-color prints are printed using standard four-color inks according to the conventional process. However, when a certain color color is found to be inconsistent, and the ink volume adjustment cannot meet the color requirements, the hue of a certain color ink may be considered. Appropriate adjustments make the ink color of the printed product conform to the original color. For example, when we printed a four-color logo, there was a clear reddish phase in the color of the superficially bright orange after superimposition, and the yellow hue had a clear lack of sensation, a large difference from the original color, and a decrease in the amount of M color ink. The increase in Y color is limited, and cannot be adjusted to the same requirement as the original ink. In this case, it seems that only by appropriately reducing the dot area of ​​the M version and increasing the dot area of ​​the Y version can the effect be achieved. Adjusting the effect of color, however, it is very time consuming and will increase economic costs, which is undesirable. The author through careful analysis and study of the printing sample, found that the entire layout of the Y-color part of the flat screen and the M color version of the flat network there is an overprint relationship, the M color version does not have a single color rendering results, so , The author germinated in the 'four-color red' ink, adding some 'four-color yellow' ink, the composition of a special spot color red ink overprint, through this treatment, light orange overlay printing layout, printing color instantly A similar effect to the color of the sample is achieved, so that the printing color of the product finally meets the requirements of the customer. In the same way, in printing a series of printed materials of different materials, the hue of a certain main color often appears to be significantly lighter due to the difference in the materials. In this regard, appropriate adjustment of the hue of a certain ink may be considered to realize the printing ink color. This is the easiest and quickest way to correct it.
Seven, use different printing process features to control the printing color
Due to the difference in the printing process, the thickness of the printed ink layer is also significantly different. For a series of prints with large differences in material, according to the print layout color and the adaptability of the material to the printing process, a suitable process is selected for printing, which also controls the printing color. An effective way. The ink layer thickness of various printing processes is approximately: Offset 3μm; Embossing 8μm; Flexoprint 10μm; Gravureprint 12μm; Screenprint 30μm, according to the basic properties of the substrate, surface gloss, ink absorption, and layout pattern In the case of structures, etc., consider selecting printing processes suitable for the ink-absorbing properties of the substrate material, as appropriate. The offset printing process is limited by the balance of ink and ink. The adjustment range of the ink coating amount is small, and it is more suitable for printing substrates with relatively good glossiness, such as coated paper, glass card, white card, offset paper, whiteboard paper, and leather card. The napkin has a soft texture, a large ink absorption, a poor tensile strength, and is easily stretched and deformed. Therefore, the napkin is more suitable for printing with a low-viscosity liquid water-based ink to obtain an ideal printing color, and the water-based ink has a huge advantage in environmental protection. Therefore, using a flexo process to print napkins is the best choice. Choosing the printing process should not only consider the influence of the print characteristics of the substrate on the printing color, but also consider the printing production cost. For example, the gravure and flexographic plate making process is expensive and is more suitable for printing long-line products.
Eight, different material series print quality control methods
Due to limitations in the scale of production of a printing plant, for example, a factory has only a single flexo printing process, and some factories have a single offset or gravure printing process. Many series of printed products are often sent to several factories for printing. . Due to the cost of production, some customers did not use the proofing process, which is often a printed material of a certain kind of material printed before, as a color reference of another kind of material print, such as the use of printed soft-printed napkins as offset whiteboard paper. A control sample of the printing color of a paper or laminating paper cup brings certain difficulties to the control of the printing color, and the offset printing is often difficult to keep up with the flexo ink. Because the flexographic ink layer is thick, the offset ink layer can be adjusted to a smaller extent than the flexographic process. Therefore, when printing a series of printed matter using different techniques, it is advisable to arrange the printing of the product using the offset printing process and the use of flexo printing, gravure printing, or post-printing of silk screen printing. This is beneficial to the control of the color of a series of printed matters. If the same offset printing process is used to print products with different materials, it is considered that the materials with good glossiness should be printed first, and the materials with poor glossiness should be arranged after printing. Because of the good glossiness of the material, the control of the amount of printing ink is relatively accurate, which reduces the chance of a large deviation in the printing color. It is worth mentioning that the use of printed manuscripts as a reference for printing color should pay attention to the effect of the light transmission performance of sample materials on the identification of color vision. For instance, the transparency of film prints and napkin prints should be high, and they should be placed on the standard side with printed samples. Table for identification.
In summary, to control the color of a series of printed materials of different materials, it is necessary to pay attention to the comprehensive consideration of the characteristics of materials, printing process technology and equipment operation adjustment, and through careful technical analysis of the manuscript, and then determine the appropriate production process plan. Not only can avoid the blindness of the production process, reduce the occurrence of printing defects, but also can better guarantee the product's printing quality, and effectively improve the production efficiency.
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