Causes of paper wrinkling in offset printing

Mechanical reasons 1 The pressure of the paper pressing wheel of the paper feeding table is uneven   Causes of paper wrinkling in offset printing

       The paper is subjected to axial force during transmission, resulting in the bulging of the middle part of the paper during the positioning of the front gauge and the formation of wrinkles after embossing.Causes of paper wrinkling in offset printing

2. The gripping force of the paper gripper row of the embossing cylinder is different   Causes of paper wrinkling in offset printing

       If the holding force on both sides of the paper holding tooth row of the embossing cylinder is insufficient, the trailing tip of the paper will wrinkle;Causes of paper wrinkling in offset printing

        If the gripping force on one side is insufficient, the corresponding trailing edge is wrinkled; If the gripping force in the middle is insufficient, the middle part of the paper will wrinkle.Causes of paper wrinkling in offset printing

3. Improper paper handover   Causes of paper wrinkling in offset printing

       In the process of paper handover before embossing, if it is not matched properly, resulting in the change of paper length at its mouth, the trailing tip is easy to wrinkle.Causes of paper wrinkling in offset printing

4. Uneven tooth pad   Causes of paper wrinkling in offset printing

       When the paper is held in its mouth, if the tooth pad is uneven, the paper edge will form a wave shape and the mouth part will be wrinkled locally.Causes of paper wrinkling in offset printing

5. The position of paper edge and gripper is incorrect   Causes of paper wrinkling in offset printing

       After the paper is positioned, if the paper is held by its teeth, the edge of the paper will be uneven and wrinkled.

6. The ink adhered on the surface of the embossing cylinder is too thick   Causes of paper wrinkling in offset printing

       The ink adhered to the surface of the embossing cylinder is too thick, which makes the paper uneven during embossing, and will also produce local short-distance wrinkling deformation.Causes of paper wrinkling in offset printing

Paper reason

1. The paper knocking marks are too deep and dense   Causes of paper wrinkling in offset printing

      Due to improper paper knocking force, the paper knocking trace is too deep and dense, and wrinkles are easy to occur at the crease of paper knocking during printing.Causes of paper wrinkling in offset printing

2. Paper strand direction   Causes of paper wrinkling in offset printing

       When the paper enters the machine for embossing, if it is a straight silk thread, it is easy to cause the silk head to wrinkle.Causes of paper wrinkling in offset printing

3. The water content of the paper is too large   Causes of paper wrinkling in offset printing

       The water content of the paper is too large, and the fiber of the paper expands. During the embossing process, the expanded fiber narrows from hypertrophy, which is easy to produce branched folds extending from its mouth to the trailing tip.Causes of paper wrinkling in offset printing

4. Influence of ambient temperature and humidity   Causes of paper wrinkling in offset printing

       The change of ambient temperature and humidity causes uneven water content of the paper. If the water content around is greater than that in the middle, the lotus leaf edge is generated, and the paper is easy to wrinkle during printing.Causes of paper wrinkling in offset printing

Exclusion method   Causes of paper wrinkling in offset printing

      After the paper wrinkling fault occurs, targeted measures should be taken to ensure the printing efficiency and quality. For wrinkles caused by the above reasons, the following measures can be taken to overcome them.Causes of paper wrinkling in offset printing

      First, the printing sheet shall be properly knocked to improve the printability of the paper, so as to eliminate the wrinkle of the next color printing.

      Second, adjust the roller teeth, so that its force is uniform, so that the printing sheet is in the appropriate position of the teeth, and eliminate the wrinkling fault caused by the imbalance of paper handover.Causes of paper wrinkling in offset printing

Third, during embossing, ensure that the paper is flat and close to the embossing cylinder.Causes of paper wrinkling in offset printing

        In addition to mechanical reasons and the reasons of the paper itself, improper use of the lining will also cause paper wrinkling. If the lining is too soft, convex, false or solid, or the lining is not tight, it will cause paper wrinkling.Causes of paper wrinkling in offset printing

       Therefore, attention should also be paid to the lining process to prevent wrinkling caused by virtual looseness of the lining.Causes of paper wrinkling in offset printing