Gravure printing paper paper printing

Gravure printing machines are generally used for the color printing of plastic films, but they are also relatively rare for paper printing. Paper printed with hot sol can be used for packaging various medical products. This is also an exploration and innovation in which companies use their original equipment for technological innovation and new product development.

The gravure printing machine prints glue on the paper products. In addition to the equipment factors, the use of paper and glue are also important factors for ensuring the quality of the packaging products. Paper thickness, toughness, tension, and the ratio of the glue will have a greater impact on product quality. There are three main aspects: First, the variety and weight of paper. Different requirements of the product, select different types of web. The second is the proportion of hot melt and temperature control. When the temperature is suitable, the glue on the gravure plate will quickly dry and solidify after being transferred to the paper, and it will be relatively smooth in the subsequent operation and winding, otherwise it will cause the traction guide roller and the paper roll to be covered with hot melt and clean up. difficult. The ratio of hot melts mainly refers to the mixture of hot melt and polyethylene wax. The more glue, the higher peel strength, affect the packaging effect; more wax, peel strength will be too low, easy to crack packaging. Therefore, do multiple tests to achieve a more appropriate ratio. Third, the amount of glue printed on paper products also has a greater impact on product quality. Too little or too many are inappropriate, too few will stick, affect the quality of the product; too much, the cost is too high.

The ideal situation is to use suitable paper and form a uniform layer of clear, non-defective layers on the surface. Due to the complexity of actual production, various factors in the production process will affect the quality of the product. Therefore, appropriate measures must be taken to minimize defects and ensure that product quality meets packaging requirements.

First, gravure printing rubber control system

The control system that affects the distribution of printed rubber has the following parts:

1. The rubber roller, a wire roller, a scraper and a glue tank system. The system determines the amount of coating and ensures that the glue spreads at a certain distribution density. Mount the surface of the tape.

2, plastic tank. The glue tank plays an important role in the printing process. Due to the melting of the hot melt there is a process that is: heating - melting - aging (yellow, black appear). To make the hot melt melt better, the glue tank must have a certain heat capacity, so that the glue tank keeps the constant temperature for a long time, and the temperatures in the tank are uniform. Therefore, it is required that the wall thickness of the glue tank be thicker, and that there should be standing ribs in the middle of the groove to facilitate heat conduction. The width and depth of the glue tank should be determined according to the width of the printing paper and the diameter of the wire roller.

3, blasting. Room temperature and ventilation conditions affect the hardening rate of the glue, and the use of one or two blowers of the printing press itself can speed up the curing of the glue.

4, winding. When you begin to wind up, be sure to hit a good bottom and stick to your heart.

Second, raw materials

1, hot sol. A general-purpose hot melt can be used. The melting points of hot melts from different manufacturers are different, and some are even more different. In order to ensure excellent coating quality, it should be carefully identified before use.

2, polyethylene wax. It is mainly used to control the fastness of bonding. Its matching ratio determines the quality of the packaging. When selecting, care should be taken not to have refractory crystals or impurities. In addition, also consider the compatibility with the hot melt, if dissolved to form a thin layer of liquid on the surface, it should be more stirring, mixed before use; otherwise, are printed on the paper are not wax instead of glue, can not be the next step produce.

3, with adhesive tape. The choice of paper is based on the user's request for selection, and the second is the choice of paper tolerance. Otherwise, the breakage will often occur during the printing process. In general, the tension of paper resistance is much smaller than that of plastic film. Therefore, it is required to be stable, slow, and uniform at the time of starting the car. Sudden rapidity and sudden stoppage will cause the paper to break and cause a great deal of waste. On the other hand, the force exerted by the paper roll on each guide roller should be consistent in direction and consistent in size, otherwise it will also be broken. Then the paper storage time, generally do not exceed one year, otherwise paper whiteness, toughness, etc. will be subject to a larger impact, this must be taken seriously, it is best to buy it.

Third, the process factors

1, the mix of plastic and cable roller matching. In order to make the amount of paper glue printed properly, the network cable is clear, different netting rolls must be taken into consideration for different amounts of glue, which is often overlooked. Generally speaking, the following principles can be followed: The larger the amount of glue, the less the cable used for the cable roller; the smaller the amount of glue, the more cable used for the cable roller. Therefore, three sets of cable rollers, ie, one set of 80 lines, should be prepared. For the highest adhesion fastness, the coating amount is also the largest; for one set of 100 to 120 lines, it is used for moderate adhesiveness; 130 to A 150-line set is used for ordinary products with less adhesiveness. In addition, the rubber roller and the cable roller must be parallel when working, and there is a certain pressure. Otherwise, it will cause the phenomenon of partial lack of network cable and glue transfer. Then, the diameter and width dimensions of the cable roller and the rubber roller are also factors that should be considered, and strive to find out the commonly used size in use, so as not to affect the production as much as possible, but also to use the rubber roller and the cable roller, resulting in unnecessary The waste.

2, the hardness of the rubber roller adjustment. The rollers in the system provide a certain amount of pressure to force the glue out of the mesh and disperse on the surface of the paper. Therefore, the hardness of the rubber roller has a great influence on the dispersion of the glue. It is worth noting that there are two aspects. First, the hardness of domestic rubber rollers is generally not high, and there are certain differences in the hardness of products from different manufacturers. Secondly, the elasticity of the rubber roller will decrease with the extension of the time of use. The hardness and hardness of the rubber roller determine the amount of glue transfer. It is necessary to select a suitable soft and hard roller to make the clear plastic cable printed on the paper clear.

3, the system's cleanup. Due to the characteristics of the hot melt, it melts by heating and cools and solidifies. Therefore, pay attention to the cleaning of the printing system. Various guide rollers, blower outlets, and two ends of the cable roller, especially when the paper breaks in the glue slot, will bring a lot of glue to the system. If the cleaning is not clean, it will cause the paper to be crushed, emptied, and not printed on the rubber. And so on.

4, driving notes. Before driving, first calculate the amount of glue. If you drive continuously, you must pre-heat the pre-packed glue, and pour it into the glue tank in the molten state. After one to two hours of constant temperature, check that the glue melts evenly before driving. Secondly, since the plate roller is not immersed in the glue tank, its temperature is low and it cannot drive. The roller should be immersed in the tank for 10 to 20 minutes until the screen roller and the glue temperature are almost the same. The glue should be liquid. In addition, when driving, the web should be straightened so that the direction of force is the same and the size is the same so that the paper is not pulled off.

Fourth, the workshop production environment

The dust in the air of the workshop will adhere to the paper, destroying the fastness of the glue. Especially at the air outlet, strong air currents will be mixed with dust particles and spread to the paper glue, affecting the product quality. Therefore, in addition to keeping the workshop clean, the filters at the air outlet should also be frequently cleaned and replaced.

The above are the factors that affect the quality of the gravure printing paper and the methods to improve the printing effect. Due to the complexity of the normal production process, a comprehensive consideration must also be taken when analyzing a certain quality problem.