Because the investment of unit type Flexography machine is too large, small and medium-sized self-adhesive printing enterprises can hardly bear it. Therefore, most of them use flat or round pressing self-adhesive trademark printing machines with compact structure and low price. This kind of printing machine is mostly refitted from Letterpress printing machine. Its ink supply mechanism and printing and stamping mechanism are more complex than those of unit Flexography machine, and it is also very troublesome to operate. To ensure high quality, the technical level of the operator is crucial. We will now conduct a brief analysis and discussion on common problems and solutions during the printing process for peer reference.
1、 Stress questions
Printing pressure has a significant impact on printing quality. Maintaining an average and constant printing pressure within the effective printing area can not only average the ink color of the printed product with small color difference, but also ensure that the print size is not disordered. Flat printing can achieve maximum printing pressure. However, due to the manufacturing accuracy and flatness of the printing plate, as well as the inability to achieve a complete average thickness of the adhesive substrate, the pressure is uneven, which affects the printing quality. One measure to solve the uneven pressure is to make a cushion, where the pressure is low, the lower part of the workbench should be padded; One is to appropriately reduce the hardness of the flexplate. However, reducing the hardness of the flexible version is limited. If the flexibility is too low, it will cause the geometric dimensions of the graphics and text to expand outward, making small fonts easily blurred. When printing on a large area, the problem of printing pressure is not easily solved. Therefore, we use the method used during hot stamping, which is to place a layer of silicone rubber plate with a 175 line mesh pattern and a hardness of 90 ° on the workbench to solve the problem of insufficient exhaust and local pressure. ł
2、 Paste plate
Small text, such as fonts below the eighth size, often causes ink to dry on top due to the small spacing between fine lines, resulting in indistinguishable adhesion between images and text. This is mainly due to the rapid drying of the ink. Our company is currently using resin offset printing ink produced by a certain ink company in Shenzhen, which has a high viscosity. In addition, the temperature is high, and the ink dries quickly. The printed products are also very fine, and the phenomenon of dry printing is quite common. When it comes to this situation, we need to first look at the problem with the flexible resin version itself. Generally, it is required that the bottom of the resin version font has a smooth feel and should not become sticky. However, due to insufficient exposure, the bottom of the font is in a sticky and soft state, which easily sticks to the ink. The ink accumulates more and dries up inside the thin lines. If it is abandoned and not used, it will also spread out the plate material. At this time, the resin plate post-treatment solution can be used for treatment. The post-treatment solution contains Sodium hypochlorite and hydrochloric acid, which can harden the bottom of the word and eliminate sticky problems. The most fundamental way is to try to find the correct exposure time and produce a resin plate that meets the scale. It is recommended to switch to a copper zinc version if the font is particularly fine. The font of the copper zinc version is not prone to dry ink, and the font is hard, making it easier to print clear strokes. In terms of operating the environment, it is important to pay attention to reducing the air flow rate. If it still does not work, appropriate slow drying agents can be added to the ink to reduce the drying speed. A relatively appropriate increase in printing speed can prevent excessive ink drying. ł
3、 Halo
Sometimes there will be a cloud like shadow on the adhesive product, which is mainly caused by uneven ink distribution. FlatteningBecause the investment of unit type Flexography machine is too large, small and medium-sized self-adhesive printing enterprises can hardly bear it. Therefore, most of them use flat or round pressing self-adhesive trademark printing machines with compact structure and low price. This kind of printing machine is mostly refitted from Letterpress printing machine. Its ink supply mechanism and printing and stamping mechanism are more complex than those of unit Flexography machine, and it is also very troublesome to operate. To ensure high quality, the technical level of the operator is crucial. We will now conduct a brief analysis and discussion on common problems and solutions during the printing process for peer reference.
1、 Stress questions
Printing pressure has a significant impact on printing quality. Maintaining an average and constant printing pressure within the effective printing area can not only average the ink color of the printed product with small color difference, but also ensure that the print size is not disordered. Flat printing can achieve maximum printing pressure. However, due to the manufacturing accuracy and flatness of the printing plate, as well as the inability to achieve a complete average thickness of the adhesive substrate, the pressure is uneven, which affects the printing quality. One measure to solve the uneven pressure is to make a cushion, where the pressure is low, the lower part of the workbench should be padded; One is to appropriately reduce the hardness of the flexplate. However, reducing the hardness of the flexible version is limited. If the flexibility is too low, it will cause the geometric dimensions of the graphics and text to expand outward, making small fonts easily blurred. When printing on a large area, the problem of printing pressure is not easily solved. Therefore, we use the method used during hot stamping, which is to place a layer of silicone rubber plate with a 175 line mesh pattern and a hardness of 90 ° on the workbench to solve the problem of insufficient exhaust and local pressure. ł
2、 Paste plate
Small text, such as fonts below the eighth size, often causes ink to dry on top due to the small spacing between fine lines, resulting in indistinguishable adhesion between images and text. This is mainly due to the rapid drying of the ink. Our company is currently using resin offset printing ink produced by a certain ink company in Shenzhen, which has a high viscosity. In addition, the temperature is high, and the ink dries quickly. The printed products are also very fine, and the phenomenon of dry printing is quite common. When it comes to this situation, we need to first look at the problem with the flexible resin version itself. Generally, it is required that the bottom of the resin version font has a smooth feel and should not become sticky. However, due to insufficient exposure, the bottom of the font is in a sticky and soft state, which easily sticks to the ink. The ink accumulates more and dries up inside the thin lines. If it is abandoned and not used, it will also spread out the plate material. At this time, the resin plate post-treatment solution can be used for treatment. The post-treatment solution contains Sodium hypochlorite and hydrochloric acid, which can harden the bottom of the word and eliminate sticky problems. The most fundamental way is to try to find the correct exposure time and produce a resin plate that meets the scale. It is recommended to switch to a copper zinc version if the font is particularly fine. The font of the copper zinc version is not prone to dry ink, and the font is hard, making it easier to print clear strokes. In terms of operating the environment, it is important to pay attention to reducing the air flow rate. If it still does not work, appropriate slow drying agents can be added to the ink to reduce the drying speed. A relatively appropriate increase in printing speed can prevent excessive ink drying. ł
3、 Halo
Sometimes there will be a cloud like shadow on the adhesive product, which is mainly caused by uneven ink distribution. The uniform ink roller of the flat press self-adhesive printing machine is a chrome plated iron roller with a diameter of 150mm that can be axially moved. Its function is to receive ink from the ink bucket roller and the ink transfer roller, evenly mix the ink, and then transmit it to the ink roller. Without the effect of the ink transfer roller, it is easy to form a halo. In addition, the inking roller is made of soft Nitrile rubber vulcanized. If you do not pay attention to the maintenance, the inking effect will decline, which will also cause halo. To solve the problem of halo is to solve the problem of uneven ink distribution in printing. You can increase the amount of ink.