The best way to master the suitability of printing

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Master the suitability of iron printing and improve the quality of color printing

at present, with the rise of packaging, the development speed of iron printing enterprises is very amazing. China has grown from more than 100 enterprises ten years ago to more than 1000 enterprises today. The development speed is fast, but because the technical management and technical literacy have not kept pace with each other, a considerable number of enterprises, including those that have introduced modern iron printing equipment, can only produce medium and low-grade products, while many medium and high-grade iron printing products also depend on imports. This is extremely incompatible with the market economy. Therefore, the improvement of the overall technical level of iron printing is imminent! The following lecture focuses on how to master the suitability of iron printing and improve the color reproduction level of iron printing

the iron plate mainly displays its quality by color effect, so the research on the suitability of iron plate should focus on the core of color, including: the printing effect of metal iron plate; The influence of iron printing ink and coating; The ideal state of printing iron pressure and the uniformity of printing iron color. First, let's understand the printing effect of metal printing. Metal printing iron includes tinplate and aluminum sheet. Tinplate, also known as sheet metal, is suitable for a thickness of 0 Between 40mm, the metal sheet for iron printing is generally divided into tinned sheet, coated sheet, ordinary sheet, etc. according to the requirements of different products, the tin plating amount in tinned sheet can be increased or decreased. For example, the tin plating amount of iron printing products such as food cans and beverage cans is higher, while the tin plating amount of products such as machine oil tanks and paint cans can be slightly lower. Due to the different surface properties and colors of the above three kinds of thin plates, the relationship between the surface color and the product color should be considered when selecting thin plates. For example, chrome plated thin plates should be used for crown caps, hot water bottles with special patterns, tin plated plates should be used for paint cans, food cans and beverage cans, and ordinary thin plates can be used for products with coatings on both sides. The general idea is that different sheets should be selected for different products

aluminum sheet is a thin sheet composed of pure aluminum with a content of more than 99.9% and a certain amount of other metals. There are two kinds of aluminum sheet: roll packaging and sheet packaging. Thickness at 0 Between 35 mm. The widening and overhauling project in 1999 must be leveled after cutting the roll shaped aluminum sheet. Stack in a dry and ventilated place. Aluminum sheet is mainly used for beverage can top and bottom covers, anti-theft covers and other products. Then we come to understand the influence of ink and coating

coating is a special process for iron printing. According to the needs of different products, it can be divided into: priming paint, white paint, inner protective paint, gloss coating, etc. Tinplate or aluminum sheet has its own inherent color of metal. However, in the appearance color of many products, it is not expected to show the color of metal. Therefore, the coating plays the role of covering the metal color. The most commonly used white paint is to cover the metal color to make the tinplate or aluminum sheet white. On a white print, the pattern rulers of various colors can play their greatest advantages

coating is applied on metal printing pieces after being extruded by roller on a roller coater, a research project launched by Masdar Institute of science and technology and the University of Manchester in the UK

iron printing ink is a special ink similar to offset printing ink but different from offset printing ink. The process of printing ink in production is: from the ink tank - ink bucket - ink roller - printing plate - printing piece (the ink film is formed on the pattern part of the metal printing piece to make the operation stable after beating up). What works here is the physical properties of the printing ink, that is, the fluidity, denaturation, elasticity, viscosity, etc. of the printing ink. In the process of iron printing, the ink is required to have flow adaptability, that is, from the ink bucket roller to the ink leveling roller should show good ink distribution and transfer. Then transfer to the printing plate evenly and accurately, and then transfer from the printing plate to the printing piece reliably and effectively in a certain state. In addition, the ink splashing, flying ink, ink roller ink scaling, emulsification and other faults in the process must also be considered together with the operation suitability. The transfer of iron printing ink is a basic and important part in the process of iron printing. When the ink is transferred from the printing plate to the metal print by the pressure of the embossing cylinder, the ink film on the printing plate breaks and is divided into two parts. One part is transferred to the print and the other part is returned to the rubber. As shown in the following figure

the amount of transferred ink is related to the viscosity, elasticity and tension of the ink itself; It is related to the amount of ink; With the fluidity of ink; It is related to the printing iron pressure; It is related to the surface properties of metal printing. In addition, the ideal state of printing iron pressure is also a subject of concern for the suitability of printing iron

the main part of the iron printing machine is composed of an ink device and a pressure device, with other auxiliary devices. Therefore, the role of the iron printing pressure in the iron printing process is very critical. In order to make a good printing iron, it is necessary to apply appropriate pressure. Excessive iron pressure not only shortens the life of the plate and pad, but also becomes the cause of ghosting. From the point of view of iron printing suitability, it is extremely necessary to maintain appropriate iron printing pressure. The printing plate cylinder and the city printing cylinder are linked by the helical gear device, and the bite position is specified by the cylinder pillow. The impression cylinder has calculated the diameter reduction so that the position can adapt to the lining. Therefore, the thickness and hardness of the plate cylinder and rubber cylinder liner are important factors to determine the iron printing pressure. That is, when the liner is hard, even if the liner is thinner, there will be considerable pressure, while the soft liner will not generate too much pressure even if it is thicker. All these should be considered globally according to the machinability and equipment accuracy of the iron printing machine

the uniformity of the final iron printing color is also important

the uniformity of iron printing color includes two aspects. One is the uniformity of the front and back colors of the same product, and the other is the uniformity of the same print. From the perspective of management personnel or specific operators, they always hope to meet the above requirements, but there are many links to be straightened out in the specific implementation. This is because there are too many influencing factors

first, let's analyze the uniformity of the same batch of products. There are many influencing factors in this regard, mainly including the factors of iron printing equipment and operation adjustment. Here, the equipment factor is the key, and the accuracy of the equipment is the main influencing factor. The second factor is the level of operation and commissioning. The uniformity of the color of the same metal print is mainly caused by the operation, followed by the equipment. In terms of control, the reflection densitometer can be used to measure and control. First set the range of standard deviation, and then understand the distance between the average deviation and the standard deviation in actual production

to master and be familiar with the relationship between the suitability of iron plate printing and color control. The purpose is to improve the strength of color control in iron plate printing, so as to raise the technical level of iron plate printing to a new level. Taiwan and the United Nations Industrial Development Organization jointly propose to strengthen international cooperation in the industrial field. (author: Wang Haohao, Shanghai Meilin can making Co., Ltd.)

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