Cause analysis and treatment of wrinkle failure of

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Cause analysis and treatment of print wrinkling fault

Print wrinkling fault is a common fault phenomenon in the process of printing production. This paper analyzes the various phenomena of wrinkle failure of printing products, and the reasons are various, including the abnormal water content of paper, and the source of the defects of printing layout structure; There are reasons for improper lining process, as well as improper printing pressure; It is caused by poor adjustment of paper teeth or too small mouth volume, as well as improper paper tapping methods, etc. Therefore, carefully analyzing all kinds of wrinkling faults and correctly grasping the printing operation and process technology are effective measures to prevent printing wrinkling and ensure the printing quality of products

I. Analysis and preventive measures of several phenomena of printing wrinkle fault

1. Printing wrinkle fault caused by paper edge curl

we know that paper is very sensitive to the temperature and humidity changes of the environment. If the temperature and humidity of the printing environment are abnormal, it is easy to make the paper stretch and change. If the water content of the paper is too low, the paper is easy to be curled around, and it is easy to wrinkle when printing. The water content of the paper is too low, and it is easy to produce static electricity, which makes it difficult to achieve normal printing. If the water content of the paper is too high, it is easy to make the paper too soft and wrinkle. Therefore, we should pay attention to strengthening the scientific management of paper at ordinary times. The room temperature of paper warehouse should be controlled between degrees and the indoor relative humidity should be controlled between%. For paper wrapped products entering the warehouse, unpack them as soon as possible, lay them flat and stack them neatly. The paper shall be stacked high from the ground and away from the wall to prevent the paper from moisture absorption and deformation. In addition, the paper should also be heat proof, fold proof and pressure proof, which is not only the basic requirement to better prevent the paper from warping and deformation, but also the necessary measure to prevent the print from wrinkling

2, printing wrinkle caused by printing layout structure defects

some papers have good flatness, but there is still a wrinkle fault during printing. This is due to the layout structure. For example, when printing the relief plate of the field and

lines, the air resistance is easy to be generated at the moment of contact between the printing sheet and the plate during the stamping process, causing the local paper surface of the printing sheet to bulge and wrinkle. In addition, the wooden bottom plate is not evenly padded and the bottom plate is not solid, so that the printing pressure is too heavy, which is easy to cause the wrinkle of printed matter. For this, we should control the technology of plate mounting and pad, and increase or reduce the pressure of light line layout, so as to avoid the wrinkle of printed matter

3. Wrinkle of printed matter caused by improper lining

the lining is the medium of imprint transfer. When the inner and outer lining layers are too soft, it is easy to bulge after the lining is pressed, and the lining is not tight enough, the surface lining paper has cracks, the lining surface is repeatedly padded or controlled empty, and the trailing part of the lining paper is not glued and flutters, which are easy to produce wrinkle of printed matter. Therefore, in the process of printing, we should pay attention to the technology of lining, so as to prevent the wrinkle of printing products caused by the loose lining and the uneven surface

4. Wrinkle of printed matter caused by wear and looseness of equipment parts

when the key parts of the machine are worn, the machine parts with linkage roller for embossing lose their due accuracy, making the machine imprint slip instantly due to a small amount of looseness, which is also the source of embossing wrinkle caused by printing a certain layout and paper. For this reason, attention should be paid to strengthening the maintenance and overhaul of the equipment at ordinary times, so that the key parts of the equipment can maintain good lubrication and high accuracy, so as to prevent the occurrence of axial or radial looseness between components and reduce the chance of wrinkle of printed products

2. Several treatment methods for wrinkle of printed matter

1. Knock the paper to improve the printability of the paper

for the paper that is thin or lacks flatness and stiffness due to deformation, such as the curling of the paper edge at the mouth of the printing sheet, it is necessary to knock the paper edge to make the paper physically change, so as to improve the flatness and stiffness of the paper edge at the mouth of the printing sheet. For the bending phenomenon in the paper, the method of horizontal or vertical hammering can be adopted as appropriate, so that the printing sheet can obtain the flatness required for printing, so as to achieve the purpose of eliminating the wrinkle of the printed matter

2. Adjust the printing pressure, and eliminate the wrinkle caused by improper printing pressure

for flexible paper that is prone to print wrinkling, try to meet the requirements of the ink volume of the layout when printing, so as to prevent the printing pressure from being added by mistake due to insufficient ink volume of the layout and weak imprinting, which will cause the print wrinkling. In addition, the adjustment of printing pressure should be achieved by placing a pad to meet the needs of the majority of customers in the industry as far as possible, and the pad should be well balanced. It is also an effective way to prevent printing from wrinkling by avoiding large-area patching on the outer lining, or even repeatedly patching the outer lining

3. Adjust the pressure of the drum's paper teeth and the position of the paper, and eliminate the loss of printing sheet handover, which is a typical wrinkle fault caused by the adjustment of energy-saving materials

when there are bad conditions such as uneven pressure of the drum in taking out the paper or improper positioning of the print sheet, so that the edges and corners of the paper are not aligned with the teeth, and the amount of the mouth of the print sheet is too small, it is easy to make the print wrinkle due to the local uneven paper surface caused by the slip during the rolling process. For this, it is necessary to adjust the biting pressure and the position of the print sheet in the tooth row, so that the edges and corners of the paper enter the biting position more, and appropriately increase the amount of the mouth, Let your teeth clench the edge of the paper to avoid the occurrence of imprint slip, so as to eliminate the wrinkle fault of the print

4. Adjust the machine brush device to make the print flat close to the drum, and eliminate the wrinkle of the print caused by the falling of the print

in order to ensure the printing quality of the automatic printing machine, a row of flat paper brush mechanisms are set at the position near the impression line of the drum. When printing soft and light paper, if the brush is too tight to squeeze the print sheet on the surface of the drum, it is easy to cause the wrinkle of the print. Properly loosen the brush to eliminate the wrinkle of the printed matter

in a word, as long as we carefully summarize our experience in practice, carefully analyze and study various fault phenomena of print wrinkling, and take various preventive measures to implement, and check and control the technology and process from the source of the fault, we can minimize or avoid various characteristics of new aluminum alloy materials, which provides more flexible choices of print wrinkling faults for the design of new vehicles, Ensure the printing quality of products

author (Kang qilai)

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