The soiling of the printing plate is divided into full-area large-area soiling and local soiling. The reasons are various. Improper adjustment of the pressure between the water roller and the printing plate, the sticky ink of the water roller, the inappropriate ratio of the dampening fluid, the improper spreading of the plate pad paper, and the quality problems of the printing plate body, etc., can easily make the printing plate dirty on both sides. During the printing process, sometimes the offset printing plate is dirty on both sides. The reasons for the dirt on both sides of the printing plate are analyzed below. Uneven water roller When adjusting the contact pressure between the water supply roller and the water channeling roller, be sure to pay attention to the symmetry of the eccentric bearing direction, otherwise it will cause the water roller to be not parallel to the plate cylinder and the water channeling roller, and the flannel of the water roller is easily axially Forced into a spiral shape, water delivery cannot be even. If the eccentricity adjustment at both ends of the water roller is asymmetric, it will cause uneven pressure of the water roller, and the side of the printing plate will easily get dirty. Therefore, when testing the pressure of the water roller, several additional points can be measured, both the two ends and the middle. In addition to accurately adjusting the contact pressure of the water roller, the daily reasonable maintenance of the water roller is also very important. 1. During normal offset printing operations, the water roller should be kept clean and free from oil stains. 2. The water roller fleece sleeve must be kept moist and have a certain amount of moisture. 3. Regularly clean the water roller. If the water rubber roller can be cleaned, it will be washed. If there is too much oil stain, it can be replaced with a new water-fleece sleeve in time to prevent the printing plate from getting dirty. Another method can effectively prevent the water roller from sticking to the ink, that is, when printing, a small amount of hydrophilic colloid substance-gum arabic is added to the water bucket solution, which can effectively increase the hydrophilicity of the water roller. The material will wipe the emulsified oil stain in the water bucket solution, and absorb the dirt ink on the surface of the water roller. The water roller is thin at both ends and thick at the middle When the water roller is processed on the lathe, it is due to the elastic body, the two ends are stressed, there is tremor in the middle and the pressure is small, most of them have different degrees of shape errors between the two ends of the middle and the middle, and there are gaps at both ends. Easy to get dirty. In addition, at the time of sewing, the two ends of the water roller sleeve are thinned and thinned, and the two ends absorb less moisture, which cannot fully wet the surface of the printing plate, which is easy to cause dirt on both sides. Remedy: The size of the cutting water rubber fleece sleeve should be consistent with the water roller, and not too short. When sewing the sleeve, the tension of the needle thread is uniform. Do not over-tighten it. There must be room for closing to avoid the water roller sleeve being too thin and thin. Plate lining size is too small In general, liner paper should be added to the bottom of the printing plate. In order to prevent both sides of the plate pad paper from getting wet and water, the horizontal size of the liner paper will be smaller than the size of the plate. However, if the size of the liner paper is too small, it will cause insufficient pressure on both sides of the printing plate, resulting in poor contact between the printing plate and the water roller and dirt. Remedy: When cutting the backing paper of the printing plate, the horizontal size is controlled to be within the range of 10 to 20mm smaller than the printing plate. Butter and motor oil use the principle of oil-water repellence to avoid wetting of liner paper and improve the use effect. If the liner paper of the roller is wetted, the shell of the roller is easily corroded. Sticking ink at both ends of the water roller reduces water transfer performance If the water content of the two sides of the printing plate is controlled too little, it will cause ink to stick to both ends of the water roller due to insufficient water supply, causing the printing plate to become dirty on both sides. There are nice quality and price Paddle board .Accessories including everything you need to enjoy your day on the water including: your board, collapsible aluminum paddle, safety leash , hand pump , waterproof bag for essentials such as cell phone and keys, and an upgraded backpack to hold everything. Inflatable,paddle,board WEIHAI HITEAM TECHNOLOGY CO.,LTD , https://www.paddleboardmanufacturer.com
August 14, 2020