Analysis and treatment of the causes of wrinkles in printed products
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
Printing wrinkle failure is a common failure phenomenon in the printing production process. Analysis of various phenomena of wrinkle failure of printed products, the reasons are various, there are abnormal water content of paper, there are also sources of printing layout defects; there are reasons for improper packaging lining, and printing pressure is not suitable; Caused by poor adjustment of the paper or the amount of the mouth is too small, as well as improper paper knocking methods and so on. Therefore, careful analysis of various wrinkle failure phenomena, correct control of printing operations and process technology is an effective measure to prevent printing wrinkles and ensure product printing quality.
I. Analysis and preventive measures for several phenomena of print wrinkle failure
1. The wrinkle of the printed product caused by curling of the edge of the paper
We know that paper is very sensitive to changes in the temperature and humidity of the environment. If the printing environment temperature and humidity are not normal, it will easily cause the paper to expand and contract. If the water content of the paper is too low, the paper is easily curled around, and wrinkles are likely to occur during printing. The water content of the paper is too low, and it is easy to generate static electricity, making it difficult to achieve normal printing. If the water content of the paper is too high, it tends to make the paper too soft and embossed. Therefore, we should pay attention to strengthening
For the scientific management of paper, the paper room temperature should be controlled between 18-22 degrees, and the indoor relative humidity should be between 60-70%. For the paper package products that are put into the warehouse, they should be unpacked as soon as possible and stacked neatly. Stack the paper away from the ground and away from the wall to prevent the paper from absorbing moisture and deformation. In addition, the paper should be heat-proof, anti-fold and anti-pressure, which is the basic requirement for better preventing the warpage of the paper and the necessary measures to prevent the wrinkles of the printed product.
2. Printed layout defects caused by print wrinkles
Some papers have a good flatness, but there is still a wrinkle failure when printing. This is due to the structure of the layout. For example, when printing a solid version and a line of the relief, the contact between the printed sheet and the printing surface during the embossing process is likely to generate air resistance, so that the partial paper surface of the printed sheet is convex and wrinkles. In addition, the bottom of the wood plate is uneven, the bottom is not solid, so the printing pressure is too heavy, it is easy to produce print wrinkles, this should be done by the good version of the pad technology, reduce the line layout Pressure to avoid the occurrence of wrinkles in the print.
3. Wrinkle of printed products caused by unsuitable lining
The lining is the medium for the transfer of the imprint. When the inner lining is too soft, the lining is easy to bulge after the lining is pressed, and the lining is not tight enough, and the surface lining paper is cracked. Repeated padding or air control, pad stickers, tails are not stuck, and fluttering, etc., are prone to wrinkles. Therefore, in the printing process, attention should be paid to the good lining process technology to prevent the occurrence of wrinkles caused by the lining of the lining.
4. Wrinkles of printed products caused by worn and loose equipment parts
When the vital parts of the machine, the parts that are linked by the roller for embossing wear and wear, the accuracy should be lost, and the machine will be slipped at a moment due to the slight amount of looseness. This is also printing a certain layout, paper. Produces the source of embossed wrinkles. To this end, we should pay attention to strengthening the maintenance and overhaul of the equipment, so that the key parts of the equipment maintain good lubrication and high precision to prevent the occurrence of axial or radial looseness between the parts, and reduce the wrinkles of printed products. Opportunity.
Second, some treatment methods for the occurrence of wrinkles
1. The paper is subjected to a knocking process to improve the printability of the paper.
For papers that are thin or lack flatness and firmness due to deformation, such as when there is a curl in the edge of the sheet of paper, the paper must be knocked to make a physical change in the paper to improve the sheet opening. The flatness and firmness of the paper edge. For the phenomenon of bending in the paper surface, the horizontal tapping or longitudinal tapping may be adopted as appropriate to obtain the flatness required for printing, so as to eliminate the wrinkles of the printed product.
2. Adjust the printing pressure to eliminate the wrinkles caused by the uncomfortable printing pressure.
For flexible papers that are prone to wrinkles, it is necessary to consider the requirements of the amount of ink received on the printing plate to prevent the printing pressure from being erroneous due to the lack of ink on the printing plate, so that the printing sheet may be wrinkled. In addition, the adjustment of the printing pressure should be achieved by the underlying pad as much as possible, and the underpad should be balanced with the foot pad. It is necessary to avoid large-area applicator on the outer lining, and even repeatedly fill the outer lining, which is also effective for preventing wrinkles of printed products. Method.
3. Adjust the pressure of the roller gripper and the position of the pick-up paper to eliminate the wrinkle of the printed product caused by the misalignment of the printed sheet. ·
When the pressure of the roller creping paper is uneven or the positioning of the printing sheet is unsuitable so that the corners of the paper are not aligned with the teeth, and the amount of the sheet opening is too small, it is easy to make the sheet in the rolling process, and the partial paper surface is caused by the slippage. Unevenness causes the printed product to wrinkle. In this case, the pressure of the teeth and the position of the printed sheet in the row of teeth should be adjusted so that the corners of the paper enter the bite position, and the amount of the mouth is appropriately increased, so that the bite can bite the edge of the paper to avoid pressure. The occurrence of the printing slip occurs to eliminate the wrinkle failure of the printed product.
4. Adjust the brush device of the machine so that the printed sheet is tightly attached to the roller to eliminate the wrinkles of the printed product caused by the falling of the printed sheet.
In order to ensure the printing quality, the automatic printing machine is provided with a row of flat paper brushing mechanism on the printing line of the roller. When printing soft and light paper, if the brush is too tight to press the printing sheet on the surface of the roller, it is easy to cause printing. Wrinkles. The brush should be properly adjusted to eliminate the wrinkle of the printed product.
In short, as long as we carefully sum up our experience in practice, we will conduct detailed analysis and research on various fault phenomena of wrinkles of printed products, and adopt various preventive measures to implement the control of technology and technology from the source of the fault. It can minimize or avoid the wrinkles of printed products of various characteristics and ensure the printing quality of the products.