The whole process of trademark printing can be roughly divided into four parts: design, plate-making, printing and post-press processing. They are interrelated and indivisible. This article briefly introduces the characteristics and requirements of the trademark screen printing process.
1. Design of trademark screen printing
The process design of trademark screen printing has the following characteristics:
1. Design for the end use of the job
Different jobs have different requirements on the paper used. For example, the label of bottled wine adopts automatic labeling method, and the bending direction after glue application is required to match the automatic labeling machine, otherwise it cannot be produced on the automatic assembly line.
2. Hollow and mosaic design
The trademark design often needs to be hollowed out and inlaid, especially for products that need to be printed with gold (silver), it must be designed as a hollowed version, otherwise the gold (silver) ink is printed directly on other inks, which is prone to darken the color.
3. Fight together
One of the distinguishing characteristics of trademark printing is to join together, as few as two, and as many as dozens. How many picture combinations are more appropriate depends on the process conditions.
(1) The difficulty of post-processing. If there are many post-processing processes for the live parts, the layout should not be too large. Otherwise, due to the poor temperature and humidity control of the printing workshop, it is easy to cause the paper to swell, which will not only affect the overprint, but also give the hot stamping and mold behind. Cutting and other processes cause problems such as difficulty in positioning and registration.
(2) Special-shaped trademarks. The area of ​​the trademark is generally not very large. For thin-shaped special-shaped trademarks that need to be die-cut, it is not advisable to join together too much, otherwise the accuracy of the die-cut plate production will affect the quality of the die-cut.
(3) Number of prints. If the number of printing is not large, the number of stitching cannot be too much, otherwise the layout is too large, and the cost of making die-cut plates is high, which will inevitably increase the cost.
(4) Paper opening number. Due to the influence of the size of the trademark, it is not possible to accurately assemble the octave, quarto, or folio versions, so the principle of saving printing paper as much as possible should be used to select the appropriate combination method.
It can be seen from the characteristics of the trademark screen printing design that an excellent trademark designer should not only have innovative design concepts and flexible design skills, but also be familiar with printing and post-press processing technology, so that the designed trademark is both novel and unique. It also meets the requirements of printing and post-press processing technology to avoid unnecessary economic losses. For example, the circumference of the trademark pattern is too close to the size of the finished product. Due to the influence of factors such as paper deformation and low precision of the die-cutting tool, the die-cut finished product is often skewed and the error is too large, which makes the product scrapped. In this case, the designer should adjust and change the design to meet the requirements of printing and post-press processing.
2. Making screen printing plate
1. The basic process of direct emulsion plate-making method
The direct plate-making method of photosensitive emulsion is a commonly used screen-making method in China at present, and its technological process mainly includes the following points.
(1) Degreasing. Before making the screen version, the screen must be degreased with a matching degreasing agent, taking care not to use household decontamination powder or descaling agent.
(2) Dry. Rinse the degreased silk screen with clean water, and use an air brush to absorb all the moisture on the plate, and then put it into an oven at 30-40 ° C to dry it thoroughly.
(3) Apply photosensitive glue. Using a suitable applicator, the diazo emulsion is evenly scraped onto the screen, usually wet-to-wet.
(4) The drying of the screen. Place the screen coated with the photosensitive emulsion horizontally in a drying oven, with the printed side facing down, and the drying temperature must not exceed 40 ° C.
(5) Supplement glue for the screen version. In order to eliminate the unevenness of the photosensitive layer of the screen, a layer of photosensitive emulsion can be added on the printing surface of the screen.
(6) The drying of the screen. Use the same method as the first drying to dry the screen again, pay attention to the drying temperature must not exceed 40 ℃.
(7) Exposure of the online version. The screen is exposed using a suitable light source, such as a metal halogen lamp, and the exposure time is determined by the grading exposure.
(8) Screen development. Spray and develop with a tap water gun of appropriate water pressure to completely rinse out the graphics on the screen.
(9) The drying of the screen. Use unused white newspaper or a hygroscopic wipe to gently wipe off excess water on the screen. If it is mass production, you need to use special equipment to absorb moisture, and finally put the screen in a drying oven to dry.
(10) Revision. Cover the pinholes or other disadvantages on the screen with a water-soluble screen filler.
Different jobs have different requirements on the paper used. For example, the label of bottled wine adopts automatic labeling method, and the bending direction after glue application is required to match the automatic labeling machine, otherwise it cannot be produced on the automatic assembly line. [next]
2. The main points of direct emulsion plate making
To make a high-quality photosensitive emulsion screen, one of the elements to pay attention to is that the photosensitive adhesive layer of the screen must be uniform and the photosensitive emulsion should completely cover the screen. First apply the glue on the printing surface of the screen plate 1-2 times, then immediately apply the glue on the squeegee surface 2-4 times, and then apply the wet to wet squeegee, and then dry it. After drying, apply glue 1 to 2 times on the printing surface to make the thickness of the photosensitive glue layer reach the final requirement. Each glue application must be carried out after the previous glue layer is dried. The main factors that determine the number of times of screen coating are the printing requirements and the fineness of the screen, including the following points.
(1) Line. For the prints with higher resolution requirements, use 90 mesh / cm or finer screen. In general, the thickness of the photoresist layer is about 15% to 25% of the thickness of the screen, and usually should be between 10 and 18 μm.
(2) Net tone adjustment. Screen printing requires a thin ink layer, so the thickness of the photoresist layer is also very thin, about 10% of the thickness of the screen, generally 4 ~ 8μm.
(3) UV ink. When printing with UV ink, the amount of ink adhesion should be as small as possible. In general, the photoresist layer on the screen printing surface should not exceed 5 μm.
(4) The quality and fineness of the screen are another important factor that determines the number of times the main layer of the screen is applied.
(5) Squeegee buckets are usually used for manual glue application. The edge of the glue bucket must be very smooth and lifted up over the entire length, so as to ensure uniform coating on the entire surface, including the center of the screen.
(6) Because many diazo sensitizers and their sensitized emulsions have strong acidic reactions, aluminum scraper buckets are easily damaged, and metal-plated scraper buckets will be oxidized after a short period of use, and then If the composition of the photosensitive emulsion is destroyed, fine foam and scum will appear in the emulsion, so a plastic non-oxidizing scraper bucket should be used.
3. Analysis of common failures and causes of direct emulsion plate-making
(1) Fisheye-shaped protrusions appear after glue application
Reason analysis: The degreasing treatment of the wire mesh before coating is incomplete, or there are dust particles on the wire mesh.
(2) Bubbles appear during the glue application process
Reason analysis: The glue applicator is running too fast, the air is filled into the mesh, forming bubbles, and the general thick wire mesh is prone to such problems.
(3) After exposure, the photosensitive adhesive layer does not adhere well
The reasons are as follows.
â‘ The photosensitive adhesive layer was not completely dried before exposure.
â‘¡ The exposure time is too short.
â‘¢The performance of the exposure lamp is not good, and the light energy is insufficient. An integrator should be used during exposure.
â‘£The sensitivity of photosensitive emulsion is poor, and the diazo component is not completely dissolved in water.
⑤ The air humidity is too high, the coated screen feels completely dry by hand, but it is not completely dry.
(4) Light scattering causes the fine layers of the image on the screen to be lost
Reason analysis: When printing, using white silk screen is prone to light scattering, and using orange silk screen can avoid light scattering to the greatest extent. However, compared with the white silk screen, the exposure time of the dyed silk screen is increased by 75% to 100%.
(5) Sawtooth effect
Reason analysis: The photosensitive emulsion coating is not good, and the photosensitive adhesive layer on the screen printing surface may be too thin.
(6) Screen printing dots stick to each other
Analysis of the reason: the screen printing requires a thinner photoresist layer. When necessary, it can also reduce the number of times the photoresist is scraped off. If the photoresist layer is thick, the amount of ink attached during printing is too large, which causes the dots to stick to each other, especially in dark image areas. This phenomenon is more obvious.
(7) Difficult to remove the film
The reasons are as follows.
â‘ After printing, the screen cannot be rinsed in time, or the rinse is not thorough, and some ink is dried on the screen.
â‘¡ Due to the influence of the solvent, the screen still contains ink, and the stripper cannot dissolve the photoresist. Before removing the film, it must be degreased again.
â‘¢ The stripping solution is not suitable.
Specification :
1, 100% handmade, convenient ,minimalist,durable
2, with strong and smooth stitching
3, Premium good nice eco-friendly PU leather
4, Any design can be made as your request
1) One main compartment clsoed by zipper, metal zipper puller
2) Variety in the style of bags, it is very convenient to put cosmetic tools or various of cosmetics into it( Sending inquiry now for more details)
Leather Pouch,Leather Coin Purse,Leather Waist Bag,Leather Makeup Bag
Guangzhou Ysure Electronic Technology Co., Ltd. , https://www.ysurecase.com