First, the optical quality of paper BaiDu. Whiteness measures the total reflectivity of light on paper. White paper with high whiteness can enhance the contrast with ink and make the color of the printed material vivid. The main factors affecting the whiteness of the paper are:
1 The degree of pulp bleaching. Pulping is mainly divided into mechanical pulping and chemical pulping. Since mechanical pulping is a method in which pulp is obtained by mechanically agitating fiber raw materials without using chemical agents to remove lignin, paper made from mechanical pulp (for example, news paper whose composition is: mechanical pulp 80%, chemical Slurry 20%) The whiteness is relatively low, and the degree of bleaching of the chemical pulp directly affects the whiteness of the paper.
2 Whether brighteners have been added to the paper.
3 Whether the paper is filled with filler. Common fillers include: calcium carbonate, talcum powder, titanium body powder, kaolin, etc. Pulp pulp in the process of mixing into the paper after the whiteness is relatively high.
4 Whether the surface of the paper is coated with paint. Paper with a surface-coating coating (such as coated paper) has higher whiteness than uncoated paper (such as books and paper), but in reality, books with lower whiteness are not too contrasted with ink. Strong, when reading is not too dazzling, it is good for protecting people's eyesight, so this beige paper has gradually become the new darling of books and periodicals printing.
2. The gloss of the paper. Paper gloss refers to the degree of paper's regular reflection of light. The gloss of the paper is related to whether the base paper is coated and whether it has undergone supercalendering. The gloss of the uncoated paper is between the gloss of the coated paper and the gloss of the coated calendar paper. The gloss of the paper is high, the gloss of the printing is correspondingly high, and the print is colorful.
3. opaque. After the opacity paper is printed, the phenomenon of print-through will often occur, which will make the graphic and text information appear disorganized and affect the quality of reading. Therefore, paper with high opacity should be used in the printing process. (If the print product has special needs, it should be treated specially.) ).
Second, the surface properties of paper 1. Smoothness. Paper smoothness refers to evaluating the flatness and uniformity of the paper surface. The smoothness of the paper is high, and the reproducibility of the dots is good, and a clear and delicate print can be obtained on the paper. Smooth and full dots are conducive to accurate reproduction of the tonality and color of the original, so papers with high smoothness (such as coated paper) are often used for printing fine prints.
The paper has low smoothness, poor reproducibility of dots, and imprints that cannot be transferred properly. It is suitable for printing on forms. At the same time, the ink may also cause local adhesion on the paper due to uneven distribution, resulting in peeling.
2. Degree of dust. Dust on paper refers to impurities that cannot be removed during papermaking. The dustiness of the paper is too high, and its roughness is relatively high. This will increase the friction in the printing process and cause the printing plate to have a reduced printing rate, which is not conducive to the reproduction of graphic information. Therefore, the papermaking process should pay attention to the application of sand removal and slag removal equipment, and pay attention to keep the workshop clean and reduce the degree of paper dust.
3. Sizing degree. Sizing is often used to measure the ability of a paper to resist water penetration. In the lithographic printing process, the ink is transferred by using the principle of oil-water repulsion. When the paper with high degree of sizing is used for printing, the ink and fountain solution are difficult to enter into the paper, thereby reducing the paper's water absorption deformation and improving the overlay accuracy. After the sizing paper is calendered, the gloss and smoothness of the paper will be increased accordingly, thus improving the quality of the printed matter. After the sizing of the paper, the glue between the rubber and the material is tightly bound to the fiber, which increases the strength of the paper and reduces the phenomenon of hair loss.
According to the different uses of paper, the degree of sizing differs from each other. For example, the newsprint ink has a dry-inking method that does not require sizing; the letterpress printing paper can be squeegee-free as it requires no fountain solution; Writing paper requires heavy sizing to avoid picking.
4. Absorption. Absorption of the paper is too large, the binder in the ink will be excessively infiltrated, and the print will lose its luster and even cause chalking. At this time, the amount of ink may be properly increased to remedy the problem. And other ills; paper absorption is too small, the ink drying speed will slow down, in the high-speed printing process will produce back dirty, unclear imprinted and other ills. At this time, we can reduce the printing speed and increase the drying time. We can also add drying oil to the ink to speed up the drying of the ink. In some special printing methods, such as UV printing, if the UV ink used does not see the light dry in time, it will also cause the printed surface to be dirty, and the back surface will be dirty.
Third, the strength of paper indicators 1. The surface strength of the paper. The surface strength of the paper refers to the paper's ability to pull off powder. The paper's performance is low. It's bad to get rid of the powder. The prints will leave spots. The accumulation of paper powder will clog the characters and patterns on the plate to cause stencils, and it will also reduce the printing rate of the printing plate.
In the alcohol dampening system, the paper powder on the printing roller will be transferred to the water tank to flow into the water tank, which will cause the performance of the dampening fluid to decline. If the hair loss is serious, it will block the water pipe and affect the normal liquid supply.
2. The tensile strength of the paper. The high tensile strength of the paper is required in the web rotary printing process, because during the rotary printing process, the blanket cylinder, the plate cylinder and the impression cylinder are always in a state of pressure, if the tensile strength of the paper is relatively high. Low is prone to paper breakage, which often causes the paper to wrap around the blanket cylinder, causing blanket and plate wear and, in severe cases, damage to the printer.
Fourth, paper other performance indicators
1. Paper moisture. When the moisture content of the paper is large, the paper is greatly deformed in the printing process, and the overprinting is inaccurate. At the same time, the tensile strength of the paper is reduced. When the moisture content of the paper is small, the paper is brittle and its toughness is reduced, and the static electricity is severe.
The paper moisture that we usually refer to refers to the equilibrium moisture of the paper, that is, the moisture content of the paper when the moisture of the paper does not change in a certain temperature and humidity state. Normally, the value is about 7%. The factors affecting the balance of moisture in paper are: 1 the type and purity of the raw material pulp; 2 the temperature of the environment; and 3 the relative humidity of the environment.
As the structure of printing presses becomes more and more perfect, the requirement for moisture in paper is not too stringent, but the requirement for balancing the moisture of carbonless paper is still quite strict, because such products are often multi-products, if the moisture content of each paper is different Larger, it will inevitably lead to the paper's drawing up and deformation, resulting in the difficulty of binding after the order of the pages, so it must be humidity treatment during printing, so that the paper's balance of moisture and the printing shop's temperature and humidity consistent.
2. Paper stretching deformation. The main constituent material of paper is fiber, and the increase of the true diameter of fiber is larger than the increase of its length. In theory, the ratio of the increase of the diameter and the increase of the diameter of a single fiber can reach 20:1. Although a lot of materials such as fillers and rubber compounds are added during the papermaking process, the water absorption and swelling of the fibers is still an important factor to be considered in the printing process.
The telescopic deformation of paper will affect the accuracy of overprinting, sometimes it will crease the paper, and it will have a more serious impact on the products (such as bar code, etc.) that must be finely printed. Therefore, the orientation of the paper, that is, the fiber, must be considered when printing. The main arrangement direction.
The quality of the paper directly affects the quality of the printed matter. We should use paper in accordance with the quality requirements of the product to achieve a full and effective use of resources. We must also attach sufficient importance to the paper's influence on the paper due to human factors in the process of transportation and storage. Paper as an important printing material, how to reduce the consumption of paper has become an important issue for enterprises to save potential.
Author: Chi Bridge
1 The degree of pulp bleaching. Pulping is mainly divided into mechanical pulping and chemical pulping. Since mechanical pulping is a method in which pulp is obtained by mechanically agitating fiber raw materials without using chemical agents to remove lignin, paper made from mechanical pulp (for example, news paper whose composition is: mechanical pulp 80%, chemical Slurry 20%) The whiteness is relatively low, and the degree of bleaching of the chemical pulp directly affects the whiteness of the paper.
2 Whether brighteners have been added to the paper.
3 Whether the paper is filled with filler. Common fillers include: calcium carbonate, talcum powder, titanium body powder, kaolin, etc. Pulp pulp in the process of mixing into the paper after the whiteness is relatively high.
4 Whether the surface of the paper is coated with paint. Paper with a surface-coating coating (such as coated paper) has higher whiteness than uncoated paper (such as books and paper), but in reality, books with lower whiteness are not too contrasted with ink. Strong, when reading is not too dazzling, it is good for protecting people's eyesight, so this beige paper has gradually become the new darling of books and periodicals printing.
2. The gloss of the paper. Paper gloss refers to the degree of paper's regular reflection of light. The gloss of the paper is related to whether the base paper is coated and whether it has undergone supercalendering. The gloss of the uncoated paper is between the gloss of the coated paper and the gloss of the coated calendar paper. The gloss of the paper is high, the gloss of the printing is correspondingly high, and the print is colorful.
3. opaque. After the opacity paper is printed, the phenomenon of print-through will often occur, which will make the graphic and text information appear disorganized and affect the quality of reading. Therefore, paper with high opacity should be used in the printing process. (If the print product has special needs, it should be treated specially.) ).
Second, the surface properties of paper 1. Smoothness. Paper smoothness refers to evaluating the flatness and uniformity of the paper surface. The smoothness of the paper is high, and the reproducibility of the dots is good, and a clear and delicate print can be obtained on the paper. Smooth and full dots are conducive to accurate reproduction of the tonality and color of the original, so papers with high smoothness (such as coated paper) are often used for printing fine prints.
The paper has low smoothness, poor reproducibility of dots, and imprints that cannot be transferred properly. It is suitable for printing on forms. At the same time, the ink may also cause local adhesion on the paper due to uneven distribution, resulting in peeling.
2. Degree of dust. Dust on paper refers to impurities that cannot be removed during papermaking. The dustiness of the paper is too high, and its roughness is relatively high. This will increase the friction in the printing process and cause the printing plate to have a reduced printing rate, which is not conducive to the reproduction of graphic information. Therefore, the papermaking process should pay attention to the application of sand removal and slag removal equipment, and pay attention to keep the workshop clean and reduce the degree of paper dust.
3. Sizing degree. Sizing is often used to measure the ability of a paper to resist water penetration. In the lithographic printing process, the ink is transferred by using the principle of oil-water repulsion. When the paper with high degree of sizing is used for printing, the ink and fountain solution are difficult to enter into the paper, thereby reducing the paper's water absorption deformation and improving the overlay accuracy. After the sizing paper is calendered, the gloss and smoothness of the paper will be increased accordingly, thus improving the quality of the printed matter. After the sizing of the paper, the glue between the rubber and the material is tightly bound to the fiber, which increases the strength of the paper and reduces the phenomenon of hair loss.
According to the different uses of paper, the degree of sizing differs from each other. For example, the newsprint ink has a dry-inking method that does not require sizing; the letterpress printing paper can be squeegee-free as it requires no fountain solution; Writing paper requires heavy sizing to avoid picking.
4. Absorption. Absorption of the paper is too large, the binder in the ink will be excessively infiltrated, and the print will lose its luster and even cause chalking. At this time, the amount of ink may be properly increased to remedy the problem. And other ills; paper absorption is too small, the ink drying speed will slow down, in the high-speed printing process will produce back dirty, unclear imprinted and other ills. At this time, we can reduce the printing speed and increase the drying time. We can also add drying oil to the ink to speed up the drying of the ink. In some special printing methods, such as UV printing, if the UV ink used does not see the light dry in time, it will also cause the printed surface to be dirty, and the back surface will be dirty.
Third, the strength of paper indicators 1. The surface strength of the paper. The surface strength of the paper refers to the paper's ability to pull off powder. The paper's performance is low. It's bad to get rid of the powder. The prints will leave spots. The accumulation of paper powder will clog the characters and patterns on the plate to cause stencils, and it will also reduce the printing rate of the printing plate.
In the alcohol dampening system, the paper powder on the printing roller will be transferred to the water tank to flow into the water tank, which will cause the performance of the dampening fluid to decline. If the hair loss is serious, it will block the water pipe and affect the normal liquid supply.
2. The tensile strength of the paper. The high tensile strength of the paper is required in the web rotary printing process, because during the rotary printing process, the blanket cylinder, the plate cylinder and the impression cylinder are always in a state of pressure, if the tensile strength of the paper is relatively high. Low is prone to paper breakage, which often causes the paper to wrap around the blanket cylinder, causing blanket and plate wear and, in severe cases, damage to the printer.
Fourth, paper other performance indicators
1. Paper moisture. When the moisture content of the paper is large, the paper is greatly deformed in the printing process, and the overprinting is inaccurate. At the same time, the tensile strength of the paper is reduced. When the moisture content of the paper is small, the paper is brittle and its toughness is reduced, and the static electricity is severe.
The paper moisture that we usually refer to refers to the equilibrium moisture of the paper, that is, the moisture content of the paper when the moisture of the paper does not change in a certain temperature and humidity state. Normally, the value is about 7%. The factors affecting the balance of moisture in paper are: 1 the type and purity of the raw material pulp; 2 the temperature of the environment; and 3 the relative humidity of the environment.
As the structure of printing presses becomes more and more perfect, the requirement for moisture in paper is not too stringent, but the requirement for balancing the moisture of carbonless paper is still quite strict, because such products are often multi-products, if the moisture content of each paper is different Larger, it will inevitably lead to the paper's drawing up and deformation, resulting in the difficulty of binding after the order of the pages, so it must be humidity treatment during printing, so that the paper's balance of moisture and the printing shop's temperature and humidity consistent.
2. Paper stretching deformation. The main constituent material of paper is fiber, and the increase of the true diameter of fiber is larger than the increase of its length. In theory, the ratio of the increase of the diameter and the increase of the diameter of a single fiber can reach 20:1. Although a lot of materials such as fillers and rubber compounds are added during the papermaking process, the water absorption and swelling of the fibers is still an important factor to be considered in the printing process.
The telescopic deformation of paper will affect the accuracy of overprinting, sometimes it will crease the paper, and it will have a more serious impact on the products (such as bar code, etc.) that must be finely printed. Therefore, the orientation of the paper, that is, the fiber, must be considered when printing. The main arrangement direction.
The quality of the paper directly affects the quality of the printed matter. We should use paper in accordance with the quality requirements of the product to achieve a full and effective use of resources. We must also attach sufficient importance to the paper's influence on the paper due to human factors in the process of transportation and storage. Paper as an important printing material, how to reduce the consumption of paper has become an important issue for enterprises to save potential.
Author: Chi Bridge
Power Board and Power supply can be repair printer and maintenance printer.
can be wholesale and retail, large stock.
Stable quality and long service life. reduce maintenance cost and labor cost.
Professional quality test person testing before shipment. 80% board are exported all over the world. promise quality.
Feel free to contact if any inquiry!
Power Board,Formatter Board,Supply Board,Power Supply Board
Dunhua Office Equipment Co., Ltd. , http://www.dunhuaparts.com