Application of the hottest thin plate technology i

2022-07-22
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Application of thin plate technology in carton industry the post press processing and pre press processing technology of corrugated board printing is in a period of rapid development, and great changes have taken place. Monochrome printing business is becoming less and less, and has gradually disappeared. Instead, color printing is emerging. In addition, flexo plate making process has also made great progress, which can effectively control and eliminate the negative impact of plate brushing (Development) inherent in the process itself

corrugated boxes are made of heavy cardboard after slotting and high-quality surface processing. In order to increase the sales volume of commodities, various manufacturers began to work hard on the outer packaging of commodities and strive to improve the attractiveness of the outer packaging of commodities. Therefore, cartons are becoming more and more packaged and commercialized

color halftone printing of corrugated board has become more and more common. The improvement of paperboard production process, the improvement of ink quality and the improvement of roller processing technology have laid a certain foundation for the application of thin plate technology, and effectively promoted the application of thin plate technology in flexographic printing technology

demand creates the market

why do corrugated customers always take the experimental machine from here? In the printing of paperboard, a wide range of plate systems are used, such as various types of plates, plates of different thicknesses, plates of different substrates, double-sided tapes of different viscosities and cushion materials of different elasticity. The time setting page displayed on the first page can be matched to form a variety of different combinations. Most corrugated board printing companies have tried to test different combinations of different types of plates, tapes, backing materials and inks, and analyzed the results

for a long time, corrugated board printing manufacturers have been longing for a special plate without any special materials, which is suitable for all plate making equipment and can adapt to tropical, subtropical and continental climatic conditions. Based on this demand, the structure and performance of photosensitive polymers have been greatly improved. They can also have very stable operating performance under different climatic conditions. Moreover, even after millions of times of printing, the ink transfer performance can still remain constant. What customers need is plates with higher flexibility and better printability. Therefore, this market demand promotes the development of thin corrugated plates

in addition, the latest digital plates have also become an important issue in corrugated box printing. The new and thinner plate for corrugated board printing has a black protective layer on its surface, which can be ablated by the laser emitted by CTP equipment

according to the development of market demand, plate suppliers have increased the size of plates. The new thin flexible plate has a layer of photopolymer layer, and the variety is becoming more and more complete. When printing with soft plates, the ink transfer performance is very good, the consistency is good, and the halftone image effect after printing is very good. Therefore, many printing manufacturers have given up their original hard plates and used soft plates for printing. In this way, the plate making time is saved, thus shortening the whole production cycle and reducing the production cost (including the cost of the material itself and the cost related to the plate processing)

control the impact of plate brushing and dot enlargement

when printing corrugated board by flexo printing, in order to eliminate the impact of plate brushing (Development), it is necessary to adjust the printing pressure slightly higher, which will inevitably lead to dot enlargement. Generally speaking, the larger the deformation of the printing plate, the more serious the point enlargement after printing, and affect the quality of the final print. Therefore, only the images with low line count and the thick Yin text can be printed, and the fine graphics and text cannot be printed

in view of this situation, in order to reduce the deformation of the printing plate and improve the quality of the final printed matter, people have taken corresponding measures. The first is to adopt the thin plate technology in the printing of corrugated board. It will take time to upgrade the market structure

secondly, the photosensitive polymer is improved to realize the standardization of the plate system. At present, this kind of plate used in corrugated board printing has been put on the market, and has been continuously improved in terms of exposure tolerance, thus improving the quality of paperboard printing. This makes the thin version technology of corrugated board favored by people

application in plate making and printing

generally speaking, thin plates with hardness between 32 and 34 shore hardness can basically meet the requirements of corrugated board printing. This plate is specially designed for color halftone printing, line and field printing (suitable for various substrate materials). After the main exposure, there is obvious color difference between the exposed part and the unexposed part of the printing plate, and the contrast is relatively strong. In this way, it is convenient to control the quality of the convex part (picture and text part) on the printing plate

this new type of photosensitive polymer plate also has some other advantages. For example, it has very good printability, even on very rough and uneven bags, cardboard or other substrates; Independent dot printing is accurate, and single dot is not lost; The small inscriptions and UPC bar codes are very clear and accurate. The gradient reproduction range is very wide. Moreover, if the printing plate is made under standard conditions, it is very convenient to optimize the gradient reproduction range. In a word, the exposure tolerance of this new type of photosensitive polymer plate may be very large when three specimens are brittle fracture

from f-flute and E-flute to n-flute and g-flute, the requirements for color, hiding power, contrast and other indicators are becoming more and more strict. Printers began to accept and adopt thin plate technology. The technical difference between corrugated board printing and folding carton printing is becoming more and more blurred and less obvious

select the appropriate plate

the plate manufacturer has greatly improved the performance of the plate, reduced the dot enlargement rate, improved the ink transfer performance, reduced the negative impact of plate brushing (Development), and improved the contrast of halftone printing. When printing fine halftone images or line drafts, it is necessary to ensure the consistency of the printed matter. In this case, it is recommended to use new thin soft plates or other thin hard standard plates. Under the action of pressure, the plate must have high elasticity and strong deformation resistance

elastic and compressible plate mounting material is a good choice. When a thin plate is used for printing, a large amount of printing pressure will be absorbed by the foam liner. In this way, the printed points are very clean and the edge outline is very clear. This requires appropriate pressure according to the type of corrugated board printed, that is, the pressure used between the thinner and harder plates and the softer plates is different

according to the diameter reduction of the drum and the different types of corrugated board slots, the best plate liner combination is determined through testing. Thin plate requires a shorter plate making time, and the deformation of film and printing plate is also relatively small. The relief depth of thin plates shall not be less than 0.039 inch, because if the relief depth is too small, a large printing pressure must be used. However, a large printing pressure may cause the paste of small negative text (or negative lines). Therefore, when using thin plate to print corrugated board, it is recommended to control the relief height of the printing plate between 0.039 inch and 0.042 inch

in order to meet some special requirements for heavy packaging bag printing (for example, printing on film or paper), or when printing on substrate with rough surface, another thick plate with hardness between 42 and 44 shore hardness can be used, which may achieve correct results

selection of the embossing roller

the function of the embossing roller is to ink the printing plate. It is necessary to select a suitable embossing roller to not only ensure that the dots are not lost, but also ensure that the ink transfer rate from the printing plate to the substrate is relatively high, and the ink color intensity is also relatively high. According to the requirements of corrugated board printing of different quality grades, the following lists the appropriate corrugating rollers:

1, B-Flute, coated paper: 356 lines/inch corrugating rollers are used, the theoretical ink transfer capacity is 4.20 ~ 4.52bcm (6.5 ~ 7.0cm3/m2), and the overall printing effect of halftone, text and lines is good

2, B-Flute, uncoated paper: the ink transfer amount is largely affected by the plate thickness and the backing material used. It is recommended to use a 305 line/inch corrugated roller, and the ink transfer capacity is theoretically 5.81 ~ 6.13bcm (9.0 ~ 9.5cm3/m2)

3, E-flute, coated paper: for this kind of substrate, the results will vary greatly with the type of plate. It is mainly affected by the type of plate, such as the hardness of plate, the matching of gasket, etc., which are very important and have a direct impact on the final result. Therefore, here we can only provide you with a rough and rough recommended value. We can use the corrugated roller with the number of lines between 356 and 405 lines/inch, and the ink transfer volume is between 3.23 and 4.52bcm (5.0 and 7.0cm3/m2)

in addition, the composition and viscosity of the ink also have a great impact on the ink transfer performance. When selecting plates suitable for all applications, always keep in mind that the interaction between the components of the system, including printing plate, plate mounting materials, ink roller and ink itself, is very important. If the selection is correct and the collocation is reasonable, high-quality and consistent prints can be obtained

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