The main factors affecting the service life of the printing plate

Currently, corrugated cartons produced in China are mostly printed with flexographic ink. Corrugated cartons produced and processed using this process comply with the environmental protection requirements we are now advocating, and at the same time greatly improve the processing speed of corrugated cartons, and use this process to shape Corrugated box printing can meet the actual needs of customers. In view of the fact that the market sells a relatively large number of types of plates, in order to make the carton printing effect and the service life of the printing plate reach its best, through long observation and practice, we summarize the following factors that affect the service life of the printing plate: :

The Effect of Water-based Ink on the Use of Printing Plates

Water-based ink is the main product used in today's flexographic printing. Water-based inks dry faster than offset and gravure inks, and have good printability and wear resistance. They are particularly suitable for the printing of paper and corrugated cardboard. :1 The transfer of ink is under the effect of printing pressure. The ink is transferred to the paperboard through the printing plate. The ink relies on the fibers in the paper to inhale the ink, so the smoothness of the paper surface is closely related to the fiber ink transfer of the paper. The smoothness of the paper surface is poor in ink absorption, whereas the ability to absorb ink is better. Therefore, how to select appropriate paper for the printing requirements of the product to be produced before printing is an aspect that affects the printing effect; 2 It is used in high-speed printing. Quick-drying inks can also easily dry on printing plates or anilox rollers during the printing process, so how to select the inks according to the production speed of the equipment is also critical, if the production equipment runs fast and the drying speed of printing inks is fast. Slow, in the production of box surface will appear ink phenomenon, which affects the actual printing of corrugated boxes If it is not the case, there will be stencil printing or inaccurate printing. There will be two situations when it is used for a long time: First, the printing plate involves half-tone dots, and the ink is dried up due to a long time without cleaning. Due to the quick-drying of ink, the product is printed at the time of printing, and the printing plate is frequently scrubbed to cause local damage to the printing plate in a short period of time to affect the life of the printing plate. Third, the PH value of the ink also has a service life of the printing plate. With certain influence, the PH value of the ink can be directly detected by using the standard PH value measuring tool. The PH value of the measured water ink can be read by the color card. Generally, the PH value of the water-based ink is generally alkaline. Most of them are more than 7 and the pH value of normal usable water-based inks should be between 8 and 9. However, not all water-based inks meet this standard. PH values ​​of inks of different formulas also have certain differences. Long-term use of PH values For large-sized aqueous inks, the printing plate should be thoroughly cleaned once a month with a low-concentration solution with a relatively low PH value to ensure the printing plate use effect.

The Effect of Excessive Pressure on the Printing Plate When Printing Stations Are Used in Printing Plates

As we all know, the greater the pressure of the printing press, the more likely it is that the printed product will appear ghosting. Otherwise, the pattern printing or the partial printing will be false. Only the pressure adjustment is appropriate and the amount of ink can be controlled so that the printed product can be printed. Clear, and at the same time will not appear out of ink phenomenon; sometimes machine operators due to the blind pursuit of the printing effect of ink and ignore the printing effect, so in the case of greater pressure, the printing plate will gradually be damaged during use, especially for dot printing Products, the effect of damage will be more obvious, often use the same printed version of the product will be printed once more than once, the print version will be quickly damaged in such use, so that the entire set of printing plates can not be used in retirement; In order to prevent excessive printing pressure or misprinting during the printing process, the liner can be properly installed under the printing plate. The liner under the printing plate has compressibility and can absorb printing pressure.

Improper wiping of printing plate can easily affect printing plate life

1 This is particularly evident in the use of dot-printing plates, which are often in use. Operators only use fuzzy or inking ink in real time. Wipe with cotton or cotton, and the dots will be wiped with cotton cloth. Excessive force or excessive force will damage the outlets within a short time, so that the desired printing effect cannot be achieved. 2 The printing plate should be cleaned or wiped with clean water or alcohol immediately after use. Production ignores the wiping of the printing plate. After use, the printing plate is placed aside until the other printed matter is printed and then the printing plate is wiped. This causes the ink to dry on the printing plate, and the dot printing plate causes paste death during the next use. , thereby affecting the printing effect; 3 dot printing version of the correct method of cleaning should be in the print version of the ink is not dry, with a soft brush or soft cotton cloth gently wipe with water or alcohol, to be the residual ink in the dot printing plate The net can be returned after printing.

The service life of the printing plate is greatly shortened due to the improper design of the designer

Through more than ten years of carton design processing and on-site operation of the machine platform, the printing plane design of the carton also has a greater impact on the service life of the printing plate. 1 The printing designer is not aware of the processing of the carton during the production process. The lines of the fonts or graphics are designed to be too small, so that the printing plate breaks after being used for a period of time, and the font strokes fall off; 2 when designing, the dots, solid bottoms, size fonts and patterns should be differentiated according to different situations. Because the actual printing of the product in the machine, the printing pressure requirements of the dot part of the machine to be small, the actual part of the printing pressure is relatively large, and some fonts and simple pattern printing pressure can be required, so in the actual design The film should be considered separately when it comes out of the film or plate, and cannot be treated in unison. Otherwise, the actual service life of the printing plate will be greatly reduced due to improper design.
Different from the choice of paper, print plate life is not the same

People involved in the carton processing industry know that the surface treatment of corrugated paper boxes varies widely. Some papers have smooth surfaces and some are rough. According to the value of the products, the paper used by the manufacturers of corrugated boxes will also be different. Because the choice of paper materials will determine the difference between the life of the printing plate will be different: 1 the surface of the paper is smooth, poor ink absorption, wear on the printing plate is small, otherwise the opposite result will appear; 2 some paper industry is not In developed areas, the papermaking process and raw materials used in the production of paper also determine the paper produced. In the actual printing, some sand materials in the paper are relatively unmeasurable to the printing plate, sometimes causing damage in a very short period of time. .

The effect of the storage of the printing plate on its service life

General flexo printing plates should be stored in places where sunlight can not be directly irradiated, and there should be a certain gap between plate and plate. It is recommended to make a plate rack to suspend processing, and the temperature of storage room is 25°C and relative humidity is more than 55% RH. In the meantime, the ventilation of the printing plate is ensured at regular intervals to prevent the printed plate from cracking due to the air being too dry and affect normal use.



(Qiu Guanghai)