In the printing production process, due to the effects of printing platen, screen board, scraper, paint printing paste, scraping operation and post-processing, it is easy to cause printing defects on the fabric, which affects the appearance of the product and Reduce economic efficiency. The following describes the shape of some defects and analyzes the main causes.
1. Inaccurate flower (wrong version, inaccurate set, wrong flower) patterns of more than two colors, all or part of the patterns on the printed fabric have one or several colors of patterns separated or stacked, If it is not printed on the position where it should be printed, it does not match the standard pattern of the pattern, which is called misalignment. Reasons: ① The gap between the printing plate and the positioner on the printing table or the Open Type Rotary Screen Printing Machine is too large. When the positioner on the printing plate is loose, the force generated by the operation of the scraper and the plate causes the printing plate to move in the direction of strong force, and the pattern Not printed where it should be. ② The printing plate frame is deformed, and the silk screen pasted on the plate frame is partially loosened or disengaged, causing some patterns on the plate to move away from the original position. ③ Each printed version of a pattern differs greatly in the degree of dryness and wetness. The wetted version is more swollen or partially loosened. When the scraper is running, the pattern of the version moves to the force direction, and the local pattern on the fabric Or all of them have different degrees of misalignment. ④During the operation of the printing plate, the printed piece or piece of cloth was pulled to move the printed pattern on the printing table. ⑤ The screen tension of each printed version stretches the screen greatly or unevenly. When affected by temperature and humidity, the screen pattern with small or uneven screen tension is easy to shift.
2. Percolation (diffusion, bleeding) The outline edges of one or more color patterns on the fabric extend outwards, and all or part of the pattern edges form rough edges with the same color and lighter color as the pattern, two types The third hue will also appear when the patterns of different colors are connected or adjacent, this phenomenon is called bleeding. Reasons: ① The content of thickener in paint printing paste is insufficient or the amount of water is too much, the viscosity of printing paste can not meet the required requirements. Due to the faster flow speed of the printing paste, the pattern color paste on the fabric flows more beyond the pattern edge, resulting in an unclear pattern contour. ②During printing operation, the speed of the scraper is slow, the pressure is large, the amount of tape is large, and the number of round trips is frequent, etc., which will make the pattern give too much pulp. Because the fabric load is exceeded, the color paste will bleed outside the pattern. . ③When the pattern area is large and the fabric has a large amount of pulp, the printed fabrics are stacked for a long time, which increases the humidity of the fabric and the pattern color paste is easy to spread out. ④ When preparing printing color paste, the mixing is uneven or the printing paste is directly diluted with water, which affects or destroys the stability of the printing paste in the emulsified state. ⑤ When printing on synthetic fiber fabrics, synthetic fibers blended with natural fibers or interwoven fabrics, because synthetic fibers are hydrophobic, the printing paste can easily permeate the pattern. ⑥ Thin fabrics with relatively sparse tissues have low pulp absorption capacity and are particularly sensitive to the amount of pulp carried. If the amount of color paste is large, it is prone to seepage.
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