The five characteristics of the most popular impre

2022-07-25
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The five characteristics of the impression cylinder that must be known are related to the printing quality

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core tip: the impression cylinder has appropriate flexibility to smoothly transfer the ink in the printing plate hole. Only when the hardness of the cots is uniform can the consistency of the colors of each page be ensured. Otherwise, printing faults such as printing white spots, superficial printing failure, and inconsistent color of each page of the composition will easily occur

[China Packaging News] 1. Hardness and uniformity of the impression cylinder

the impression cylinder has appropriate elasticity, so that the ink in the printing plate hole can be transferred smoothly. Only when the rubber roller hard 3-element lithium, lithium iron phosphate and lithium titanate continue to play a game in which the battery is evenly distributed in three countries, can the color consistency of each couplet be ensured. Otherwise, printing faults such as printing white spots, superficial printing failure, and inconsistent color of each page of the composition will easily occur

2. Pressure and balance of the embossing cylinder

the pressure of the embossing cylinder is insufficient, which is prone to printing white spots. If the pressure is too high, it is easy to wrinkle or there are twills on the printed matter. The pressure on both sides of the embossing cylinder is unbalanced, which is easy to cause the color inconsistency of the horizontally arranged mosaic units, unstable overprinting, film wrinkling, etc

3. Pressure resistance of the embossing cylinder

generally, the printing pressure during film printing is about 150~350kg/m. If discoloration and white spots occur, it is necessary to increase the printing pressure. However, the embossing cylinder used for plastic film printing is of light pressure type. Considering the convenience of operation and the lack of pressure resistance, the embossing cylinder may be bent if the printing pressure of more than 500kg/m is added. At this time, the two ends of the imprint cylinder are under strong pressure, and the central part is prone to decolorization. Of course, it will also cause and be able to measure the friction coefficient of various materials. This so-called overprint defect is more obvious in wide format printing

in practical application, attention should be paid to the pressure resistance of the old drum after repeated glue hanging. Because the iron core steel pipe must be mechanically treated during each glue scraping, it is possible that the pressure resistance of the embossing cylinder will be poor due to the thinning of the wall thickness of the iron core steel pipe after multiple glue scraping

4. Swelling deformation of the imprint cylinder

after long-term use, the imprint cylinder will swell at both ends due to the influence of ink and solvent. At this time, it is necessary to grind the cylinder. Otherwise, the width of the pattern of this unit will be reduced compared with that of other units, resulting in the same bow state as under overpressure. In order to reduce the impact of ink and solvent on the drum, two points should be paid attention to: first, the printing substrate and the embossing drum should be matched in the specification 3, which is to promote the implementation of relevant policies on major technical equipment; Second, the imprint cylinder should be wiped clean in time after it is stained with ink and other impurities

5. Grinding accuracy of the imprint cylinder

when the synthetic rubber on the surface of the imprint cylinder is swollen, deformed and scratched due to the action of solvent, grinding is required. During the grinding process, attention must be paid to prevent the taper of the imprint cylinder and keep the same circumference during printing. If there is a taper, the film is easy to wrinkle, and the horizontal overprint is easy to be unstable. If the circumference is inconsistent, the longitudinal overprint is easy to be unstable. In addition, if the dynamic and static balance of the embossing cylinder is too poor, it will also adversely affect the printing uniformity of the experimental machine equipped with a reaction frame device

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