The main points of flexographic printing technology (on)
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
Flexographic printing This emerging printing process, after years of unremitting efforts by people of insight in the printing industry in China, has achieved rapid and steady development in many printing manufacturers and achieved good economic benefits. In terms of commodity packaging, high-quality flexo-printed products can be seen everywhere, often making the printing industry stunned. There are many excellent prints: cigarette packs, beer labels, etc.; more self-adhesives, quite a part of the drugs entering the famous joint ventures in China. , food, daily chemicals, industrial products, labels, shopping malls, etc.; there are wine boxes, medicine boxes, hamburger boxes, bowl seals, toothpaste hoses, battery labels and other packaging; more food, women and children, daily chemical BOPP , PET, PVC film and other flexible packaging, as well as corrugated boxes and so on. At the 4th International Flexo Gravure Technology Equipment Exhibition in Shanghai in June this year, more delicate flexo products will be displayed. It is safe to assume that the quality of flexographic printing in China is comparable to that of lithographic and gravure printing. The situation has been formed and the market development space is very broad. Few people now doubt the feasibility of flexographic printing, and its advantages are fully affirmed. There are quite a few printing manufacturers, especially packaging color printing companies, which include flexographic printing in the development direction of the company as a new economic growth point for the company.
The main reason for the normal development of flexographic printing is related to the maturity of the related equipment, materials and processes, as well as the improvement of localization, but the most important factor is that the process technology of flexographic printing is correct. Use. Because flexographic printing is a new technology, it is to be mastered by people. The technical quality of corporate personnel plays a particularly important role in flexographic printing. The technical quality is characterized by the skill of equipment operation, the rational selection of materials, the correct formulation of the process, and the orderly production management. As long as the configuration of the equipment, the performance of the materials, the key points of the process technology, and the practical implementation in the production process of the printed matter, the qualified products can be produced, and the quality can be recognized by the users, and the business market of the enterprise can be expanded. The economic benefits of flexographic printing can also be guaranteed.
However, there are still some printing manufacturers that introduce flexo printing equipment. Due to the lack of certain technical support, the equipment is difficult to operate normally, the quality of the products cannot be guaranteed, and the economic benefits cannot be discussed. Analysis of the reasons, in fact, it is obvious: there is a certain gap between the overall technical quality of flexographic printing and the actual production needs of such printing manufacturers, the effective use of equipment configuration, the correct matching of flexographic materials, the rational formulation of printing technology, and operation The level of work of personnel, etc., can not reach the basic level of normal production, thus affecting the normal production of flexographic printing, which is the stage that many flexographic printing manufacturers have experienced. It turns out that if we can provide targeted technical support to such printing companies and help solve some of the weak links, the flexographic printing level of these enterprises will increase rapidly and the economic benefits will increase significantly.
Then, how to make flexographic printing develop healthily in China! We believe that improvements in process technology are key. In response to this problem, the main points on the manuscript, process and technology in the flexographic printing are now presented, and some simple introductions are made in conjunction with the actual production. I believe that it will be helpful for colleagues who are engaged in flexographic printing or will be engaged in flexographic printing. This makes the printing company less or not detour in the development of flexographic printing, which is the purpose of this article.
First, printing the original
Printed manuscripts are the basis and basis for printing plates. The patterns, characters and colors on the printed originals need to be conceptually designed and designed according to the sales characteristics of the products, and then the plate-making and printing are used to reflect the practical effects of the product packaging.
1.Feasibility
Whether it is a user's manuscript, a design company's manuscript, or a self-designed manuscript, the printer must ask the designer for the manuscript: the design of the design must be fully understood in the design process; the manuscript must be fully considered for plate-making and printing. The feasibility of the process operation. The so-called feasibility: the designer's choice of the pattern, text and color in the original must first meet the production requirements of flexographic plate making and printing; secondly, it should be suitable for the actual level of equipment, materials and operation of the printing manufacturer; The only practical standard for packaging is to ensure that the original design and flexographic printing meet the ideal quality standards.
It is necessary to point out that: most of the current manuscripts are designed by computer. In order to obtain the beautiful visual effect of the manuscript, the color images are often used, and the functions of color printing, gradation, jigsaw and deformation are especially used. Such as a rainbow pattern. If we choose the lithographic method, such printing originals rarely have problems with plate making and printing. When choosing the flexographic printing method, it is necessary to discuss with the designers the feasibility of coloring or rainbow effect in the plate making and printing process.
2. Less choice of color photos
Flexographic printing has not yet been able to reproduce a colorful hue of a color photograph as a pattern as well as lithographic printing. If you copy a beautiful art picture, such as calendars, pictures, samples, etc., it is not the specialty of flexographic printing. Although various very delicate flexographic printing samples have appeared, they are only in the stage of proof printing, and there is still a big gap in actual production compared with lithography. The color picture and color inkjet are superimposed on the layered screen of the halftone change of 3 to 4 colors by color separation plate making. Since flexographic printing belongs to letterpress printing, when the screen printing is used, the highlight portion is difficult to reproduce, and the dark portion is not changed obviously, so it is difficult to reflect the natural transition of color and the rich effect of layering. Moreover, flexographic printing is most likely to avoid "unlimited" (the percentage of dots is less than 1%). The original designer should be required to avoid excessive highlights. In the transition of the hierarchical network, let the highlights of the dots transition as much as possible, and let it go to the “extension of the design draft (bleeding area), that is, not to change the level. In the design draft. If the original does need to have a highlight part, persuade the designer: according to the current plate quality and plate making technology, the plate maker should be allowed to keep 1% to 2% of the dots in the highlight point to obtain Close to the effect of highlights. Which color dots are retained depends on the main color of the manuscript.
3. Use spot colors
We have to tell the designer to consider the use of spot colors when conceiving artwork. In the packaging design, the spot color has a unique decorative effect. For the packaged product, it is a product logo, brand logo, and purchase logo, which has a strong advertising effect. Reasonable and ingenious use of spot colors can play a finishing role in decorating design. Whether it is lithography or gravure printing, the selection of spot color printing is quite a lot. Printed spot color is the strength of flexographic printing. Its color saturation is much better than lithography, and it is not inferior to gravure printing. This is an important factor for flexographic printing to be widely accepted in packaging products.
4. Non-printing manuscript
It must be pointed out that there are quite a few printing manufacturers. The "printed manuscript" he obtained is a real sample of printed matter, and there are real samples of lithographic or gravure printing. It is really "difficult" them to use the actual sample as a printed manuscript to make the flexographic printing plate companies to make plates. For such an "original", it is necessary for the designer to re-copy "a printed original" by the computer before it can be used for plate making and printing. How this manuscript is done exactly the same as the original print, and it must conform to the process of flexographic printing, which is a cumbersome task. In this regard, the printing manufacturer should carefully analyze the printing process of the printed sample, and discuss the key points of the printed manuscript and the technical points to be discussed below, and discuss with the technical staff of the plate making company to complete the plate making. From a technical point of view, we do not advocate the use of such printed "originals".
5. Set up a craftsman
It is recommended that the printer set up a craftsman, and it is necessary for the craftsman to control the quality of the printed manuscript. Because the craftsman knows the requirements of the company's products, equipment status, process characteristics, characteristics of raw materials, technical level of employees, post-press processing and user requirements. The craftsman can combine the conditions of the company to make the printed manuscript meet the production quality standards in plate making and printing. The work of the craftsman is not replaced by other people.
Second, the process points
After the printing manuscript is determined, the craftsman will formulate the color separation process of the printing plate according to the characteristics of the printing process of the factory, and provide a reference for the plate making company, so as to ensure the production quality of the flexographic printing product. Professional plate-making companies generally accept color-printing according to the usual process if the printing manufacturer does not propose technical requirements after accepting the printed manuscript. Because the degree of understanding of the printed manuscript is not the same, and the familiarity with the flexographic process, the degree of understanding of the actual use will lead to a large unrealistic situation between plate making and printing production. Things that cause repeated iterations or re-productions occur frequently, resulting in material and time wastage. Therefore, the craftsman will develop the color separation process, and the company will make the plate making. If you don't understand, you can communicate and discuss with each other to ensure that the success of the plate making is beneficial to both parties.
The craftsman needs to pay attention to the following points during the process:
1. The four-color mesh version, the text lines, and the full version of the field should be distinguished.
The craftsman needs to know the production principle of the four-color separation plate, and it is necessary to know the other text lines and the color separation requirements of the full version. It is not like lithographic printing, nor is it like gravure printing. The four-color network cable and text lines of the same color cannot be made on the same color plate as the real one. Of course, the dots cannot be made on the same color plate as the real one. This is because the line of text is not the same as the amount of ink required in the field. If it is made on the same plate, after the quantitative transfer of the anilox roller, the ink amount (small amount) of the dot and the character line is satisfied, and it cannot be satisfied. The amount of ink on the ground (large amount) needs. Conversely, to meet the needs of the field, the lines of text must be imprinted. Therefore, on the same color plate, the text lines and the field should be divided into two plates. Small text, thin lines and large characters and thick lines should also be divided into two plates, which means that the color group configuration of the flexographic printing machine is better than other printing. The reason for the machine. Of course, it is necessary to provide color separation opinions on the hollowed-out fonts used in the design of printed originals, hook lines, adjacent colors, spot colors, and post-press processing such as hot aluminum and indentation.
2. The color separation can be used in spot colors, and spot colors should be used as much as possible.
If the spot color is often overprinted by four-color dots like lithographic printing, it will cause great trouble for flexographic printing and printing, which is not advocated by us. Even in lithography, there are not a few in the use of spot color printing in packaging printing. The use of spot color printing for the flexo is its main feature. For some special color products that require special attention, you can also use special color overprinting. The spot color of flexographic printing, the color of which is bright and saturated is obviously different from the lithographic printing, and the gravure printing method is preferred. We must make full use of the distinctive feature of the flexographic printing plate.
3. Specially eye-catching spot colors can also be used in color overlays.
Flexographic printing of spot colors, generally one color can achieve its color requirements. For some special color products that require special attention, you can also use special color overprinting. The color separation sheets of the two stacked plates are separately produced separately. The overlapping parts of the two large-format large-format graphics are the same, and there are some differences in some parts, such as large text, hollow text, solid blocks with small text and lines, and color separation film production. One of them should be considered to enlarge the line or close the line: about 0.05 to 0.1 mm, and also enlarge or close the second line, about 0.10 to 0.2 mm. At the same time, it is necessary to consider that there must be a primary color of the printed color version on the color selection, and a secondary color of the other printed color version. Such a color arrangement is very necessary. It is conceivable to select a text, a line, a dot, etc., which are required to have a small amount of ink in a two-color version. Since the graphic is brought into one of the color overprinting plates, the purpose of the color combination is achieved, and the text, line or textured version is also made, and the printing plate color number is not actually increased.
4. The imposition size depends on the product structure.
The size of the printing plate to be arranged by the craftsman according to the size of the finished product must take into account both the vertical and horizontal dimensions. The circumference of the plate cylinder is determined longitudinally, and the width of the printing web is determined laterally. Flexographic printing is converted into the circumference of the printing plate by the repeated circumference of the printed imprint, and is customarily converted into the number of teeth of the printing plate. Regardless of the flexo presses produced in Europe and the United States, or the domestic flexo presses, the British CP gear system is now used for size calculation: 8 teeth per inch = 25.4 mm long, and 1 tooth is 3.175 mm arc length. Selecting the number of teeth of the plate cylinder is to determine the repeating circumference as an integral multiple of 3.175 mm. The size of the imposition is generally determined by the repeating circumference of the plate cylinder of about 80 to 100 teeth.
It is recommended that the craftsman should not make the repeated circumference of the printed imposition. Practice has shown that the larger the repeating circumference, the larger the plate area and the larger the plate roll. The large plate roller makes the staff inconvenient to operate; at the same time, the relative printing speed of the large printing plate cylinder is slowed during printing, and the water-based ink is easy to dry on the printing plate; the large-area printing plate also brings an increase in the plate making cost. Multi-connection imposition of product registration difficulties and other ills.
5. The printing color sequence technician should know that the flexographic printing color sequence is basically the same as the letterpress printing color sequence, but the lithographic color sequential method must not be used. When determining the printing color sequence, the printed original of the four-color screen version should be analyzed for pattern color. The common color order is yellow, magenta, cyan, and black. There are also yellow, black, magenta, and blue color sequences. Because the water-based ink has high color density, strong hiding rate, thick ink layer, bright color and low light transmittance. The color sequence of the four-color screen cannot be exchanged at will.
For the spot color printing, the order of light and dark is generally adopted, and the light ink is printed first, which can make the dark ink color bright after being overprinted. For spot colors printed by the overlay method, the color sequence of the primary and secondary colors is the primary color and the primary color is printed.
6. Printing
Flexographic printing usually requires one color of water-based printing or UV printing at the end of the color sequence, which is done by the printing unit. In addition to enhancing the gloss of the imprint, it is also to enhance the physical properties of the imprinted surface to meet the needs of post-press processing, as well as the practical requirements of commodity packaging, and become an indispensable process.
The flexographic printing is available in both water-based varnish and UV varnish, and can be arbitrarily selected according to product requirements.
The printed light is divided into a full version of the printed light and a partial printed light.
1 full-printing is printed by a special printing roller (rubber roller, seamless plate).
2 Partial printing needs to be made into a printing plate, which is glazed according to the required parts of the printed product.
Many packaging prints that need to be pointed out must use partial printing to meet the post-printing requirements of the product.