The hottest method of high density printing

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High density printing method

release date: Source: China paper industry

in the packaging and printing link, sometimes high density printing method is needed. Today, China's paper industry starts with high-density printing. Let's introduce the relevant principles and applications in detail

explanation and use

when the sales of silk printed clothes fall to some extent, designers will be more committed to finding a new visual experience that can attract consumers' attention. Maybe high density printing is what they are looking for

with this method, various colors can be printed, and with a little time and effort, a careful printer can be proficient in high-density printing. Next, we will discuss the details of this new method, including the whole process from design pattern screening, plate making, ink treatment to printing and drying. Like other new things, this new scheme also needs to be tested. Even Sandvik's dual phase steel has many successful utilization cases at home and abroad, which are wrong to adapt to different printing plants. So don't be afraid of mistakes

pattern selection

this is the first and perhaps the most important step you need to consider. Line thickness and pattern size are also decisive factors for the success of high-density printing process. For example, after the printing process is completed, the thin lines will look better three-dimensional than large-area printing. Small area printing design, especially the right angle, compared with large area printing, printing ink is easier to hang on the hole. Generally speaking, you must be very familiar with which pattern types are suitable for high-density printing, and you should avoid using this technology for inappropriate patterns. There are also many patterns that will greatly enhance the visual experience if they are processed in 3D. You need to use these to your advantage

plate making

the thickness of the ink layer is determined by the thickness of the cloth yarn and the plate thickness. Plate making can adopt the method of direct coating of photosensitive emulsion, direct/indirect method, or capillary film, which will be introduced one by one below

for most thick plates, the commonly used may be the mesh (per inch). You may want to use a lower than normal cloth tension, such as Newton. Thick version and thick ink accumulation require a larger distance. Maybe improving the tension can be achieved. With this concept, don't think about your printing pattern too "high". If you think so, you will make the distance of the version too close, and make the appropriate distance impossible

in any case, you need to prepare a suitable degreaser to clean the yarn. Wait for sufficient drying time before coating or pasting (indirect film)

direct photosensitive emulsion film is achieved by repeatedly coating on the printing surface until the required coating thickness is reached. This will take a day or more. Because each coating requires drying to a moisture content of less than 4% (it takes 30 minutes to 1 hour, depending on the photosensitive emulsion you use and the drying conditions) before applying the next layer. After all the coatings are completed, you also need to let the template dry further (such as overnight) before exposure, because a version that is not fully dried will not have a good exposure effect

how to choose the appropriate photosensitive emulsion also needs further research. The best choice is one with high solid content. The higher the solid content, the less likely it is to shrink when dry. In addition, use fast exposure emulsion to minimize exposure time. It also takes a long time to expose the micron film layer to me

● single component light sensitive polymer emulsion has high solid content and fast exposure speed

● diazo based photosensitive polymer has high solid content, but the exposure speed is not fast enough

● the solid content of diazo based photosensitive emulsion is not high, and the exposure speed is the slowest. (the higher the solid content of diazo based photosensitive emulsion, the slower the exposure speed)

any kind is available, but I suggest using photosensitive polymer, because it has the fastest exposure speed and good shrinkage control

the first step is to apply wet coating on both sides of the plate, and then apply a little more force on the ink surface. This enables the photosensitive emulsion to "settle" on the printing surface. Place the plate on a horizontal shelf with the printing side down

after drying for a certain time, it enters the thickening stage:

thickening can be achieved by several different methods:

1. Standard coating: use a fillet scraper to apply two layers of coating from bottom to top (the middle is not dry), and the inverted version will be wet coated twice from the opposite direction on the printing surface. Call this coating 1. Marking the coating will help you know exactly how many times you have coated. Now let it dry, and then repeat the above action until the expected thickness is reached. Leave enough time between each coating to dry. According to your requirements for thickness, you may require eight, ten or more layers. When painting the third and fourth layers, the middle of the version may be thicker than the edge. If so, you need to paint the edges one to several times to make the thickness of the template consistent. You can pour a small amount of emulsion around instead of in the middle. Repeat twice in each direction to make a standard coating, which will make the emulsion stay only around the plate. When the eighth or more layers are achieved, it needs to be repeated many times to make the thickness consistent. After coating, leave enough drying time. My suggestion is overnight

2. Tape assisted coating: stick the tape along the periphery of the frame, but the width between the tapes should not exceed the scraper. This will help to increase the distance between the scraper and the plate and allow a thicker emulsion to accumulate with each operation. Calculate how many layers of tape to use according to the base thickness. For example, if your tape thickness is 3mil (1mil=25 microns), for a film layer 300 microns thick, you need four layers. In order to achieve the required thickness of the plate, you may need to stack the tape, taking into account the shrinkage factor. Apply two coats in each direction and carefully keep the scraper "riding" on the tape. Remove the tape before drying to avoid tearing off the dry photosensitive emulsion. Then put the plate on a horizontal shelf with the printing side up. For a thicker version, you can repeat the operation as needed, that is, after each coating, stack a new tape, and then carry out the next round of operation. Leave enough time for drying in the middle of each coating and enough time after completion. My suggestion is still overnight

3. Scraper coating: this method requires a support plate to provide a plane for the ink surface to be placed downward on it. Accordingly, this board is smaller than the inner edge of the basket, but higher than the frame height, so that it can be connected more closely with the eye. Stick the tape along the outer edge of the plate, but ensure that the width between the tapes does not exceed the coating knife and the support counter. Stack the tape together (as before) to reach a thickness and finish the coating at one time (considering shrinkage). At the end of the tape, where the scraper starts and stops, leave extra width to remove unwanted photosensitive emulsion and keep the plate clean. Now pour the photosensitive emulsion, which is also a high-tech talent cultivation and output base in the field of polymer surface materials, on one end of the plate, put down the scraper along the tape at the same end, and then slowly and stably push the scraper. When finished, place the plate on a horizontal shelf with the printing side up. Then let it dry long enough -- at least overnight. One disadvantage of this method is that such a thick layer may cause irregularities on the surface. The reason is that bubbles rise from the emulsion or are surrounded by dry emulsion near the surface. But this is not the problem itself. Think about the effect of exposure with a base plate containing bubbles? Moreover, if you use this method, you'd better place the emulsion long enough before coating to let the bubbles disperse, and ensure that your technology will not bring new bubbles in the next steps. This is similar to the direct/indirect method of using capillary film patches. This version is made by first coating the film with sensitive emulsion, then placing the film face up on the table, pasting the printing surface of the plate on the film, and then applying photosensitive emulsion on the ink surface with a scraper. After drying, peel off a protective film on the back. This method greatly improves the firmness between film and yarn

first of all, you have to consider which kind of film to use. As the sensitizing emulsion must be designed according to the specifications of hydraulic universal testing machine, there are diazo type and photosensitive compound type films. The aspect that does not need to be considered is the solid content. Because the indirect film itself is dry, and the solid content is 100%. There is no need to consider the shrinkage rate, just simply decide what you need. You have successfully completed the series development and thickness of plastic melt gear pump

then you also need a support plate, a small roller, a blunt or rounded scraper, and a jade layer photosensitive emulsion that can work with this film. Put the film emulsion face up on the support plate, and then put the plate printing face down tightly on the film. Stick adhesive tape on the inside of the plate, and the enclosed area is slightly smaller than that of the film, which helps to deal with the remaining photosensitive emulsion and keep the inside of the plate clean. Pour photosensitive emulsion into one end, hold a scraper, and slowly push it along the plate with a standard printing method. This can be coated with a thin layer of photosensitive emulsion. When it dries, it will stick the yarn and film together. Then put it on the dryer, leave enough time for it to dry, and then peel off the backing protective film

now you can start exposure, or you can "roll" another layer on it. In order to do this, you can put the printing ink face down on the support plate. Drop a drop of photosensitive emulsion on the film, and put on the second film, starting from the edge. Then start rolling the film with a roller to drive away the bubbles until the whole film is completed. Leave enough drying time, and then peel off the backing layer. (at least one company now produces a kind of direct/indirect film, each layer can be glued together before you stick it to the plate. And there is no need to use photosensitive emulsion; you just need to simply peel off the protective layer and stick it to another layer, and then press it together with a roller. Press the second or more layers to achieve the thickness you want.)

carefully stick the capillary film on the wet (with water) plate, and absorb the emulsion on the yarn through capillary action. Although you can stack two or more layers of photosensitive films together to increase the thickness, it will have a better effect if the film has enough thickness in the original direction (the thickness that can be achieved now is 1000 microns; this kind of film can reduce your printing time from one day to less than an hour; the disadvantage is that each of them is worth $50 or more)

direct photosensitive emulsion and direct/indirect film have the choice of diazo type and photosensitive compound type. Similarly, after the film is dried, the solid content is not a problem. The exposure time of photosensitive compounds is very fast. What we need to do now is to determine the thickness. Capillary photosensitive film is simpler to use than direct/indirect film because it uses water to stick the emulsion to the hole through capillary action. Thick photosensitive polymer films are available in various specifications

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