As a direct representation of the product, the label should bring consumers a strong visual impact. Because flexographic printing has bright colors. Brightness and other features have become the preferred method of label printing. This article will give a brief introduction to the printing of labels on unit-type flexo printing machines.
Choice of color order
At present, the graphic parts of labels printed with flexographic plates are mainly field, line, text, etc. The printing materials used are mostly paper, aluminum foil, plastic film, stickers, etc. When printing absorbent substrates with water-soluble or solvent-based inks, the infrared hot air drying will cause the material to bulge, which will affect the accuracy of overprinting. Therefore, care should be taken when considering the printing color sequence to avoid such problems. Color plates containing large areas of solids should be printed in the back unit as much as possible, because the substrates absorb a large amount of ink and then undergo infrared drying. The fluctuation of the solid unit is naturally larger than that of other units. Overprinting also has a greater impact in the printing process. If such units are printed after text and lines, it will more or less bring a certain positive impact on overprinting. If you have to place the solid part in the front color group for printing, you can consciously increase the compensation in the up and down direction slightly to compensate for the loss caused by the swelling of the printing material, making the overprint more accurate.
Precautions for plate making
1. Trap
When making a flexographic plate, a certain amount of trapping is conducive to printing registration, provided that the trapping size is appropriate. If the trap is set too small or does not perform trap processing, it will cause poor registration (with white leakage); while if the trap is set too large, a large outline will appear on the edge of the printed product, which will affect the Visual effects, which affect the overall effect of the label.
2. Layout Design
Because flexo printing basically uses roll paper for printing, especially the application of seamless sleeve technology, paper is greatly saved, but some flexo printing machines cannot achieve online die cutting, and still need to undergo subsequent processing (cutting, etc.) Only finished products can be produced, so when designing the layout, full consideration should be given to leaving sufficient margin for subsequent processing, and the paper saving rate should not be considered one-sidedly and the qualification rate of subsequent processing should be ignored.
Selection of raw and auxiliary materials
When printing labels with a flexographic printing plate, the choice of raw and auxiliary materials will directly affect the quality of the printed product, so the choice should not be limited to unit price, but should take the quality of the printed product as the first element and the comprehensive product Make a summary analysis of costs to make a choice. The bulk of raw and auxiliary materials that need to be considered are mainly paper and ink.
1. Paper
Generally speaking, the label pattern is mainly on the ground, which puts forward certain requirements for the smoothness, whiteness and glossiness of the paper. If you want to obtain a satisfactory label printing effect on the spot, the smoothness of the paper must be high, so as to ensure that the printed product has a uniform density value, so that the surface of the printed product does not cause flowering. Paper with higher gloss and whiteness can enhance the contrast between ink and paper, make the picture clearer, and make the flexo ink show more vivid effects. Therefore, when choosing paper for flexo label, The two indicators of gloss and whiteness are particularly important. Compared with the above two indicators, the opacity of the paper has a greater impact on the quality of the flexo label. Therefore, the whiteness and gloss of the paper should be selected under the condition that the opacity of the paper remains consistent, and the general whiteness should be Above 85%, the gloss should be above 55%.
In addition, because flexo printing generally uses roll paper for printing, the tensile strength of the paper is an important selection index. Only good tensile strength can ensure that the paper remains stable and continuous during the entire printing process, and keeps the label to maintain a good overprint accuracy. In addition, the surface strength of the paper is also an important selection index. Only the paper has a good surface strength. It makes the field printing full, and does not cause the phenomenon of unevenness and color on the surface of the printed product.
2. Ink
Due to the bright colors to be given to the label, the proportion of pigment in the ink will be increased to a certain extent, but this will have a certain impact on printing. If the proportion of the pigment is too high (more than 35%), the viscosity value of the ink will become higher, and the thixotropy of the ink will become larger, which will affect the transfer of the ink during the printing process. At this time, the ink must be stirred as necessary. And as far as possible, put the ink in a suitable temperature (20 ℃) ​​to store. [next]
In the selection of ink, the particle size of the ink and the drying performance of the ink should also be considered. Especially when there is a large area of ​​color on the label, and there are text, line or mesh tone images, it is necessary to consider that different patterns have different requirements for the drying speed of the ink, so that the printed product is clean and tidy (there is no paste) , Plucking phenomenon). In addition, excessively thick pigments will cause certain wear on the anilox roller, and attention should also be paid when selecting ink.
In short, you should strive to save when selecting raw and auxiliary materials, but you can not only consider the price factor, you should consider it from the perspective of comprehensive cost, according to the product qualification rate. Comprehensive evaluation of man-hour consumption rate, etc., in order to choose the appropriate printing materials.
Printing environment requirements
When applying flexographic printing labels, environmental factors are important. We know that the graphic part of the label has a large area on the ground, as well as text, lines and mesh tone images. Due to these limitations, it will have a certain impact on the drying of ink. The drying of ink on printed text, lines and other parts The speed will be accelerated due to the volatilization of ammonia and amine substances. At this time, the micro environment of the ink needs to be improved. A humidifying device is installed at the ink tank to suppress the volatilization of such substances, thereby controlling the drying rate.
In addition to controlling the microenvironment, the control of the overall environment during the printing process is also very important. Flexo printing is highly sensitive to the environment. When printing different types of paper and different patterns (mainly on the ground or lines) When labeling, the choice of humidity is different. Generally, waterproof paper printing requires higher humidity. When printing large areas on the ground, the humidity is lower. Excessive ambient temperature will affect the drying effect of ink (water-based ink, solvent-based ink), causing printed products to paste and other phenomena; too low temperature will cause the viscosity value of almost all types of ink to increase, resulting in reduced fluidity of the ink , Inconvenience to printing, so it is necessary to stabilize the printing environment temperature and humidity within a certain range.
In China, the four seasons in the northern region change significantly, the temperature and humidity differ greatly, and the climate is mainly dry. It is best to close the printing environment and install equipment such as humidifiers and air conditioners to create an environment suitable for flexo printing; and The climate in the south is unique to flexo printing. However, due to the rainy weather in the south, dehumidification in the workshop should be an important point in creating a flexo printing environment. The ambient temperature and humidity range suitable for flexo printing are generally: the temperature is around 25 ° C, and the humidity is between 50% and 60%.
The quality of the operator
In label flexo printing, the human factor is also critical. The operator should mainly have the following qualities.
1. High sense of responsibility. Responsibility is the first priority. If you do not have a sense of responsibility, it is futile to talk about anything.
2. Have a certain understanding of mechanical principles and electrical knowledge. When operating the flexo printing machine, the mechanical and electrical characteristics of the printing machine can be fully considered, unnecessary waste in printing can be avoided, and some problems existing in the printing machine can be eliminated.
3. Have a certain knowledge base of chemistry. When adjusting the ink, you can consider it from a physical and chemical point of view, so that the ink can achieve the best use effect.
4. Master various printing processes. Only by mastering various printing processes, can we promptly feed back some design problems, make the label design as suitable as possible for flexographic printing, so as to save raw and auxiliary materials and avoid waste.
5. Good at summing up. Only by promptly summarizing and refining the problems that occur in printing can we continuously improve our capabilities.
At present, flexographic printing is favored by packaging and printing manufacturers due to its environmental protection, bright colors, stability and other characteristics, and its proportion in label printing is also increasing. Therefore, how to make use of its characteristics is becoming a flexographic work. A subject of the author. It is believed that flexo printing will occupy a more important position in label printing on the premise that the country vigorously advocates environmental protection.
A training desk is a table designed specifically for activities such as training and meetings. It has characteristics such as durability and ease of movement, which can meet the needs of different groups of people. Training desks can be classified into various categories based on their materials, structure, and other aspects. Below will be a brief introduction to the classification of training desks.
1. Material classification
The materials of the Training Chair mainly include wooden boards, PVC boards, etc. Training desks made of wood usually have strong stability and durability, making them suitable for long-term meetings or training activities. The training table made of PVC board has certain safety performance and is generally more lightweight.
2. Structural classification
The structure of training chairs mainly includes single tables, combination tables, etc. A single chair is the most common training table, and each training table is independent and can be adjusted as needed. Combination refers to the combination of multiple seats together, usually in the form of geometric shapes or rows, suitable for use in large training venues. A stackable table is a training table that can be folded and placed together, saving space and facilitating storage and handling.
Training Table,Tea Table,Coffee Table,Visitor Table
Foshan Shengshi Zhihui Technology Co., Ltd. , https://www.officer-furniture.com