The printing industry in the modern printing industry develops from monochrome to six-color and eight-color. The efficiency has evolved from multi-process to one-step molding, integrating printing, cutting, embossing, bronzing, and laser. In the process of electromechanical integration, production also inevitably brings a series of new problems. Trademark bending not only affects the appearance of the brand, but also directly impairs the user's suitability for use on the machine. More severely, it causes dissatisfaction to the user and stops using this product. Class trademark. How to effectively solve and control the occurrence of trademark bending in production is of great significance to improving product quality and satisfying users' needs.
Why does the paper bend in the printing process? We know that paper is generally composed of chemical wood pulp, mechanical wood pulp, and a coating layer. Fibers in such ingredients will have different tensile deformations at a certain speed, pulling temperature, and relative humidity.
From the experiment, it is known that under certain conditions of pressure and humidity, the greater the tension, the higher the temperature, the greater the deformation of the paper.
In the process of one-step forming of gravure multi-color machine, the paper is subjected to 20-35daN pulling force, 25-40daN pressure, and drying temperature 60°C-100°C. After many times drying, moisturizing, stretching, and recovery, the paper is produced in different degrees. Deformation, but also in the printing, due to the application of ink, but also caused by the paper on both sides of the different stretching, deformation, recovery, and thus appear in the finished product trademark bending phenomenon, especially the poor quality of the paper will appear severe curling.
In response to the phenomenon of bending in the production of trademarks, we have taken the following measures to solve the problem of trademark bending.
First, paper control According to our many years of practice and repeated tests, trademark water should be controlled at 8% is more ideal, and the general water content of reel paper is between 4% -6%, low or even about 3%, There is a certain gap between the finished product moisture. In order to reduce the bending of trademarks, the first choice is to choose the place where the paper is produced and the brand, and to choose a brand of paper with normal moisture content and less influence by the outside world; the second paper must enter the production site for balanced moisture for a certain period of time. 4-7 days; the third is to scientifically control the moisturizing process of the production process to ensure that the paper humidity is conducive to printing and avoid bending.
Second, the control of ink, solvent In the printing process, due to the paper on one side of the ink is applied to facilitate the two-sided deformation of the paper, causing bending.
We know that inks, resins, trademark patterns, and solvents evaporate have different degrees of influence on the bending of the trademark. Therefore, in the production, we guarantee the design, color, and color to meet the needs of users. For comparison, inks must be selected for their high solubility, good performance, and low susceptibility to paddles; the thickness is generally not more than 35μm in the platemaking process according to product requirements; the solvent must be used in a balanced solvent balance, ie, it must not be too volatile. At a certain temperature (generally no more than 80°C), the product does not stick.
Third, the speed of the car, pull the coordination of the relationship in the printing process under certain conditions, the higher the printing speed, the greater the degree of trademark bending; conversely, the printing speed is certain, the greater the pull, the greater the trademark bending. In the production of equipment to play the efficiency, and can not be used to reduce the speed to solve the problem of trademark bending, we must choose reasonable tension parameters to solve quality problems. For example, during running, the speed is 130m/min, the tension before tension is 20daN, and the back tension is 34daN. This is an ideal parameter. As for the actual parameters, it can be adjusted according to the printing effect of the paper.
Fourth, the effect of drying temperature and air volume The higher the humidity inside the drying oven, there are certain benefits to the printing process, but the temperature is too high, the trademark bending phenomenon will appear. Therefore, the general level of printing will be controlled at 55 °C -70 °C. For large area printing, the temperature is generally controlled between 75°C and 90°C. Drying box inlet pressure and exhaust volume is too large, the paper moisture is low, the trademark bending is serious, the general dry air pressure is 80-90mmH2O.
Fifth, the production process of process aids in the production due to the impact of the workshop environment, the higher the ambient temperature, humidity, paper absorbency increased, the greater the possibility of trademark bending; but the ambient temperature, humidity is too low, the air is too dry, Decreasing the moisture content of the paper can also cause the trademark to bend. Therefore, for finished products, it is generally required that the plywood be bundled, the plastic bag sealed, and the corrugated carton packaged, to avoid prolonged exposure to the air, to reduce the contact environment of the finished product of the trademark, and to prevent the trademark from being deformed during storage. Excerpted from China's packaging year appraisal 1999
Why does the paper bend in the printing process? We know that paper is generally composed of chemical wood pulp, mechanical wood pulp, and a coating layer. Fibers in such ingredients will have different tensile deformations at a certain speed, pulling temperature, and relative humidity.
From the experiment, it is known that under certain conditions of pressure and humidity, the greater the tension, the higher the temperature, the greater the deformation of the paper.
In the process of one-step forming of gravure multi-color machine, the paper is subjected to 20-35daN pulling force, 25-40daN pressure, and drying temperature 60°C-100°C. After many times drying, moisturizing, stretching, and recovery, the paper is produced in different degrees. Deformation, but also in the printing, due to the application of ink, but also caused by the paper on both sides of the different stretching, deformation, recovery, and thus appear in the finished product trademark bending phenomenon, especially the poor quality of the paper will appear severe curling.
In response to the phenomenon of bending in the production of trademarks, we have taken the following measures to solve the problem of trademark bending.
First, paper control According to our many years of practice and repeated tests, trademark water should be controlled at 8% is more ideal, and the general water content of reel paper is between 4% -6%, low or even about 3%, There is a certain gap between the finished product moisture. In order to reduce the bending of trademarks, the first choice is to choose the place where the paper is produced and the brand, and to choose a brand of paper with normal moisture content and less influence by the outside world; the second paper must enter the production site for balanced moisture for a certain period of time. 4-7 days; the third is to scientifically control the moisturizing process of the production process to ensure that the paper humidity is conducive to printing and avoid bending.
Second, the control of ink, solvent In the printing process, due to the paper on one side of the ink is applied to facilitate the two-sided deformation of the paper, causing bending.
We know that inks, resins, trademark patterns, and solvents evaporate have different degrees of influence on the bending of the trademark. Therefore, in the production, we guarantee the design, color, and color to meet the needs of users. For comparison, inks must be selected for their high solubility, good performance, and low susceptibility to paddles; the thickness is generally not more than 35μm in the platemaking process according to product requirements; the solvent must be used in a balanced solvent balance, ie, it must not be too volatile. At a certain temperature (generally no more than 80°C), the product does not stick.
Third, the speed of the car, pull the coordination of the relationship in the printing process under certain conditions, the higher the printing speed, the greater the degree of trademark bending; conversely, the printing speed is certain, the greater the pull, the greater the trademark bending. In the production of equipment to play the efficiency, and can not be used to reduce the speed to solve the problem of trademark bending, we must choose reasonable tension parameters to solve quality problems. For example, during running, the speed is 130m/min, the tension before tension is 20daN, and the back tension is 34daN. This is an ideal parameter. As for the actual parameters, it can be adjusted according to the printing effect of the paper.
Fourth, the effect of drying temperature and air volume The higher the humidity inside the drying oven, there are certain benefits to the printing process, but the temperature is too high, the trademark bending phenomenon will appear. Therefore, the general level of printing will be controlled at 55 °C -70 °C. For large area printing, the temperature is generally controlled between 75°C and 90°C. Drying box inlet pressure and exhaust volume is too large, the paper moisture is low, the trademark bending is serious, the general dry air pressure is 80-90mmH2O.
Fifth, the production process of process aids in the production due to the impact of the workshop environment, the higher the ambient temperature, humidity, paper absorbency increased, the greater the possibility of trademark bending; but the ambient temperature, humidity is too low, the air is too dry, Decreasing the moisture content of the paper can also cause the trademark to bend. Therefore, for finished products, it is generally required that the plywood be bundled, the plastic bag sealed, and the corrugated carton packaged, to avoid prolonged exposure to the air, to reduce the contact environment of the finished product of the trademark, and to prevent the trademark from being deformed during storage. Excerpted from China's packaging year appraisal 1999
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