1. Printing pressure and paper deformation    Analysis Of Printing Pressure And Paper Stripping Force

      Paper is a material with plastic deformation, and the plastic deformation characteristics of different papers are also different.Analysis Of Printing Pressure And Paper Stripping Force

      Under the action of large printing pressure, the width and the length of the two corners of the trailing tip of the paper with large plastic deformation will expand slightly, resulting in inaccurate overprint, especially in the trailing tip of the paper.Analysis Of Printing Pressure And Paper Stripping Force

      The greater the printing pressure, the more obvious the deformation of the paper. Therefore, when printing the same batch of products, the pressure of each color printing plate should be as consistent as possible, Analysis Of Printing Pressure And Paper Stripping Force

       but sometimes the pressure should be adjusted according to the specific situation. For example, the printing pressure of multi-color offset press is often decreasing in random groups.Analysis Of Printing Pressure And Paper Stripping Force

      The deformation of paper is closely related to the yarn of paper. Considering that the overprint error caused by the deformation of paper under the action of printing pressure in general offset press is more difficult to adjust along the axial direction than along the radial direction, so during printing, Analysis Of Printing Pressure And Paper Stripping Force

      the longitudinal direction of single sheet paper should be parallel to the axial direction of drum as much as possible, and the yarn direction of printing paper must be the same for the same batch of products,Analysis Of Printing Pressure And Paper Stripping Force

       In order to ensure the overprint accuracy, the same batch of products must not be printed on paper with different strands.Analysis Of Printing Pressure And Paper Stripping Force

       Under the action of printing pressure, due to the fan-shaped deformation of the paper, the image with high overprint accuracy or the part that plays an important role in the subject should be arranged near the mouth during prepress processing and plate making, because the paper deformation near the mouth is small during printing, which is easy to overprint accurately.Analysis Of Printing Pressure And Paper Stripping Force

2. Paper peeling tension and paper deformation

      The paper printed in the embossing area is held by the paper teeth of the drum, forcing it to separate from the blanket, and the ink on the printing plate is used as the medium to adhere the printing sheet to the surface of the blanket with strong adhesion. Analysis Of Printing Pressure And Paper Stripping Force

       At this time, the fiber tissue on the printing sheet is affected by forces in two directions, one is the downward holding force of the paper teeth on the paper, and the other is the upward adhesion of the ink on the paper. Analysis Of Printing Pressure And Paper Stripping Force

       The direction of these two forces is opposite. When the printing sheet is stripped from the blanket, the trailing tip of the paper is easy to curl and does not fit with the embossing cylinder to form a refractive angle, which is called the stripping angle. Analysis Of Printing Pressure And Paper Stripping Force

       If the adhesion of the ink is large, the longer the printing sheet is peeled and pulled down by the paper teeth, the greater the stripping angle, the greater the stripping tension, Analysis Of Printing Pressure And Paper Stripping Force

       the stripping deformation of the paper also increases, the paper is stretched radially along the drum, and the overprint accuracy decreases.Analysis Of Printing Pressure And Paper Stripping Force

      During the printing process, if the gripper teeth of the embossing cylinder have enough gripper force to ensure that the paper does not displace, the stripping tension becomes the main factor affecting the stripping deformation of the paper, and its deformation depends on the following aspects:Analysis Of Printing Pressure And Paper Stripping Force

(1) The nature of paper. The paper with large plastic deformation has large stripping deformation, and vice versa.Analysis Of Printing Pressure And Paper Stripping Force

(2) The time between the printing pressure and the cylinder. The greater the printing pressure, the longer the embossing time, the longer the contact time between the paper and the ink on the blanket, and the greater the stripping deformation.Analysis Of Printing Pressure And Paper Stripping Force

(3) Ink receiving area of paper surface. The larger the inking area, the thicker the ink layer, and the greater the stripping deformation.Analysis Of Printing Pressure And Paper Stripping Force

(4) Viscosity and adhesion of ink. The greater the viscosity and adhesion of ink, the greater the stripping deformation, and vice versa.Analysis Of Printing Pressure And Paper Stripping Force