Some common defects in the most popular flat scree

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Some common defects in lithographic printing and their preventive measures

1. Inaccurate flowers; In printing two or more sets of printed fabrics, one or more colors in all or part of the patterns are separated or overlapped

(1) the cloth shall be flat and firm. The paste on the surface of the rubber guide belt must be evenly distributed, with consistent thickness and moderate viscosity, so as to meet the requirements of "sticky, thin and uniform", which is conducive to the accuracy of the flowers

(2) thoroughly clean the rubber guide belt. The cloth paste and printing color paste on the surface of the rubber guide belt are thoroughly cleaned by washing, keeping them clean and flat, which is conducive to the next use cycle

(3) reasonably arrange the order of printing plates. From the point of view of pairing, the pattern plates with close pairing relationship should be arranged in adjacent positions. After the fabric absorbs the printing paste, it will cause shrinkage, especially for the pattern with a large amount of paste absorption, the shrinkage will be greater. The farther the printing plates are separated, the more color paste scratched on the fabric from other patterns will also increase. At the same time, the shrinkage of the fabric will increase, resulting in difficulty in flowers

2. The pattern outline on the pasted fabric is not clear, the periphery of the pattern is rough and not bright and clean, the color and color permeate each other, and the fat flowers are pasted, which is inconsistent with the original

measures: before printing, the semi-finished product must be dried, the printing paste viscosity is moderate, and the lifting and moving of the printing plate are in a constant position. During scraping, it can be completely repeated in the original position, so as to ensure good reproducibility and clear pattern outline

3. The thin stems and white stems of the fine pattern of the pressing mark are pasted by the printing frame, or pressed unevenly, which will produce fish scale spots

measures: when printing, handle the plate connection between the two plates to prevent overlap at the joint. If it is the relationship of pattern structure that brings difficulties to the opening and connecting plate, on the premise of not affecting the original pattern, the large ground pattern can be crossed * inserted or other patterns can be appropriately extended to form a decorative pattern, so as to avoid the horizontal linear overlap at the butt joint of both ends of a plate. For large pieces of surface and large flowers on the ground, the paste with good levelness should be selected as the color paste, which is conducive to uniform fabric sizing, bright and clean patterns and plumpness

4. Therefore, the absorption point must be unconditionally used. Regular color paste dots of different sizes appear on the food grade resin fabric, which are scattered in a certain range around the pattern. The condition remains the same, and their shape and distance are basically the same

measures: adjust the rising speed of the plate properly. It is required to have buffer space when the plate is separated from the fabric to prevent the CPU frequency (11.0592Mhz) and comparison voltage from being stable or drifting when the color paste is separated from the plate? If there is a problem of faulty welding, it will splash instantly. In the selection of paste, attention should be paid to reducing the viscosity of the color paste to ensure the printing effect

5. Pattern Photocopying (pattern double printing) there are undesirable pattern and color Photocopying on the warp, weft and edge of the pattern on the printed fabric, resulting in the deformation of the pattern

measures: when stretching, it should be tightened according to the tension required by the stretching process, so as to prevent the plate from loosening when the screen is stretched and scraped back and forth with the scraper, so as to ensure the stability of the plate. For example, the foaming agent is used to protect the illegal Road, and the rubber blanket, scraper and scraping pressure should be correctly installed and adjusted

source: Foreign Trade Forum

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