Causes and elimination of scraper damage in the ho

2022-07-24
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Causes and elimination methods for damage of gravure preprint equipment scraper

in gravure printing, although the phenomenon that the doctor blade is worn into crescent shape in the image and text area rarely occurs, once it occurs, the printed matter will be scratched or even connected, and the oil will be pasted or adhered in strips according to the international law, which will seriously affect the rate of genuine products and delay the delivery time. How to prevent the abrasion of scraper caused by scraper, printing plate and ink, and how to solve the problems

I. measures to prevent damage of the gravure preprint equipment scraper

1. it is necessary to shut down for half a day or longer to clean the ink tank. In addition to pouring out the ink and cleaning the ink tank and printing plate, a top cover should be added above the ink tank to prevent dust from falling in

2. for the positioning scraper, the elasticity of the scraper can be improved by adding a spring pad at the pressing shaft core at both ends

3. for the moving scraper, the rubber gasket or foam plastic gasket on both sides of the scraper can reduce the hard friction

II. Causes of scraper wear and troubleshooting

1. when the scraper is not straight or has damage marks, it is necessary to replace the scraper

2. if the angle between the scraper and the drum is not appropriate, the scraper shall be corrected

3. in case of poor cylinder processing (such as too deep plate lines or poor aluminized materials), the printing plates shall be replaced. Zoom in and out at will

4. the position of the printing plate is not appropriate. Generally, you only need to adjust the printing plate

5. the ink particles are large and hard, or there are impurities and sand particles, which will lead to the strong adhesion of the ink to the printing plate. At this time, it is necessary to adjust or replace the ink

III. causes and solutions for severe abrasion of gravure cylinder

cause I: poor quality of printing plate chromium plating

solution: check the thickness, hardness and smoothness of chromium plating layer

reason 2: the surface of gravure cylinder is uneven

adhere to the control of relatively low measurement accuracy. Cleaning (it is better to clean after each experiment) solution: grind the surface of the printing plate cylinder, or re engrave the gravure plate, or re chrome plating

reason 3: there are impurity particles behind the doctor blade

solution: filter the ink with a filter device of at least 25 microns

cause 4: the angle and pressure of the doctor blade are incorrect

solution: check and adjust the settings of the doctor blade

reason 5: there are abrasive pigments in the ink

solution: re mix the ink with pigments with weak abrasiveness

reason 6: poor ink grinding effect

solution: replace a batch of new ink, or regrind the ink with unsatisfactory grinding effect

reason 7: the ink dries too fast

solution: reduce the amount of solvent, reduce the drying speed, or use slow drying solvent to prepare ink

reason 8: pH value of ink fluctuates

solution: keep the pH value of the ink within a specific range

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