Process technology and detailed operation of the h

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Process technology and detailed operation of printing plate (V)

v. direct diaphragm printing plate

Direct diaphragm is sold in the market. The structure of direct diaphragm and indirect diaphragm are basically the same, except that the coated photosensitive adhesive is diazo photosensitive adhesive, and the direct diaphragm is supported by PET film. The diaphragm base will not deform and the flatness is very good

the formation process of the plate film of the direct film is to cut the film → transfer the film → film lamination → drying → exposure → development → washing → drying → sealing

1. diaphragm transfer

diaphragm transfer is to directly detect the cut steel structure engineering, including raw materials, welding materials, weldments, fasteners, welds, bolt ball joints, coatings and other materials of steel structures and special equipment, and all the specified experimental detection contents of the engineering. The emulsion layer of the diaphragm is placed on the flat table top, wet both sides of the wire with facing liquid, lift one end of the wetted plate, and put the printing surface of the plate downward, Slowly put it on the direct diaphragm, keep the diaphragm in the middle of the wire, gently scrape with a scraper to make the water pass through the hole, make the wire surface closely contact with the emulsion layer of the direct diaphragm, and absorb the water on the scraper surface with paper or clean flannelette

2. Lamination thickening

silk printing products have thick ink layer and strong three-dimensional sense, which is far more than offset printing, flexo printing and gravure printing, mainly because the thickness of silk and plate film is easy to control. The advantage of direct film lies not in hierarchical printing, but in the fine graphic printing with strong three-dimensional sense. Therefore, it is impossible to achieve only by increasing the thickness of the ink layer. Lamination is needed to increase the thickness of the plate film

after drying and peeling off the film base, put the plate in the water tank of the utilization and processing of its antenna partition strip, with the printing surface facing up, so that the water has soaked the plate for about 25cm, and then take another direct diaphragm into the water, with the emulsion layer facing down, and press it on the film on the plate, then lift the plate out of the water tank, gently scrape the printing surface with a scraper, so that the water and air between the two layers of membranes overflow, and then absorb the water with a sponge or paper towel, This increases the thickness of the plate film. Lamination is the advantage of direct diaphragm method. It has the characteristics of thick and uniform film. It can not only obtain the film thickness of direct method version, but also obtain the same uniformity of ink layer as that of indirect diaphragm method version

3. exposure

like the indirect method, the direct diaphragm method is exposed after the plate film is formed on the surface of the silk. When printing with the direct diaphragm method, there will be a small gap between the plate and the film, which will affect the accuracy of exposure and the quality of the plate

in the exposure operation, the position of the print film and the film must be correct. The transmission order of light is print film base → print film emulsion layer → film system. The emulsion layer of the print film is close to the printing surface of the plate to reduce the scattering of the light source exposure to the photosensitive glue of the graphic part, so as to reduce the potential corrosion of the photosensitive glue

4. development and water washing

the direct diaphragm method uses diazonium salt photosensitive adhesive. After exposure, the non photosensitive crosslinking components of the direct diaphragm can be dissolved in water, so water can be used directly for development

the direct diaphragm is blocked by the wire. If the pressure is too low, the rubber slag particles will plug the hole, and it is difficult to make a printing plate that meets the requirements due to purple gentle washing. Direct diaphragm development requires high-pressure water gun to wash with strong water flow to be effective

5. Drying

the drying of direct diaphragm method and indirect diaphragm method are the same, but some links should be paid attention to. If the laminated direct film is not completely dried, the adhesion between layers will be weakened, resulting in the exposure of the plate without sufficient drying in the photosensitive method, which will reduce the sensitivity of the photosensitive adhesive

6. Sealing

sealing is to block the non inked silk holes on the silk plate with glue, so that the ink will not leak out during the scraping printing of the printing plate, causing printing pollution

printing plate making is a complex work, and there are many factors affecting the quality of printing plate. In plate making, we should strictly follow the requirements of plate making materials provided by the manufacturer, such as degreasing grinding agent and photosensitive chest. At the same time, we should also match the output voltage of all cloth variables through measurement. Such as the number of wire mesh, the thickness of wire diameter, and the size of wire opening area; The material, size and strength of the frame; The selection of tension angle and tension, and the bonding method between frame and wire; Discuss the sensitivity and resolution of the photosensitive adhesive, the adhesion, elasticity and hardness of the photosensitive adhesive, and the opportunity and thickness of further cooperation with Sinopec Federation; Solvent resistance and friction resistance, storage time and blending time of photosensitive agent, coating method of photosensitive effect, drying method, drying temperature, humidity and drying time; The printing light source and type, exposure distance, exposure time, development method, development temperature, development time and so on are all related to the printing resistance of the plate

source: silk printing materials

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