Reasons for discount and wrinkling of the most pop

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Reasons for discount and wrinkling of offset sheet fed lithography

1 The moisture content of paper is unevenly distributed. If the water content of the four sides is greater than the middle, that is, the ruffle phenomenon will occur, and the wrinkle of the trailing part will occur. If the water content of the four sides is less than the middle, that is, the tight edge phenomenon of the paper will occur, and the wrinkle of the middle part will occur

2. The pressure of the paper pressing wheel of the paper feeding table is uneven. The paper pressing wheel is a device that controls the flatness, constant speed and positioning of paper conveying. Due to the unequal pressure adjustment of each wheel, the paper is affected by the axial force during the conveying process, resulting in the paper bulging in the middle during the conveying and still maintaining the state of bulging in the middle during the positioning of the front gauge. After stamping, the bulging cannot be eliminated, resulting in the wrinkling of the trailing tip

3. The biting force of the paper teeth of the embossing cylinder is different. The paper biting force of the roller's paper biting teeth should be strong and strong, and the resultant force of each paper biting should be equal. If the biting force of the two sides of the teeth is insufficient, the paper will wrinkle the trailing tip. If one side bites, do you know how many parts the friction and wear tester is composed of? What tasks are each part engaged in? If the force is insufficient, the corresponding trailing edge will wrinkle. If the bite force in the middle is insufficient, the trailing edge in the middle will wrinkle. If the middle is seriously insufficient (bite force), and the speed difference between the printing rollers is large, the trailing tip may be crushed and damaged

4. Improper paper handover. During the short-range handover of the paper before being embossed, if the length of the paper edge of the bite changes (becomes smaller), it is easy to wrinkle the tip and even break the paper edge

5. The height of the dental pad varies greatly. When the paper is bitten, the edge of the paper is uneven (bite) but wavy, which will produce short wrinkle deformation close to the bite

6. The paper tapping marks are too deep and dense. Due to improper and improper paper tapping force, the paper tapping marks are deep and dense, so there are paper tapping wrinkles on the paper tapping creases

7. The corner of the paper is at the half tooth position of the paper teeth. After the paper is positioned, the paper corner is bitten half or less by the roller. As a result, the corners of the paper are often uneven and the edges of the paper are wrinkled

8. There is too thick accumulation on the roller of RS232 interface in the machine promotion of Jinan Shijin big brand manufacturer. The ink on the surface of the imprinting cylinder is too thick, making the paper imprint uneven, resulting in short-distance wrinkle and deformation of the bite

9. Paper fiber arrangement direction. When the paper enters the machine for imprinting, the fiber arrangement direction is straight strand, and the paper is easy to wrinkle the silk head

10. The water content of the paper is too large, and the fiber of the paper itself is fat. Under pressure, the fat fiber will narrow from fat, which is prone to wrinkle and deformation from the bite to the trailing twig

the above are the main reasons for paper folding. However, how to judge whether the discount wrinkle is caused by the paper itself or by mechanical reasons is also crucial, which determines the direction for us to solve and deal with quality accidents

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