Precautions for the most popular offset printing w

Editor's note: China's printing industry has introduced a large number of advanced printing machines. These printing machines have the characteristics of high automation, fast printing speed and good product quality. However, with the increase of service life, the degree of wear and damage of the equipment also increases. In addition to natural wear, some spare parts are accelerated wear and damage caused by poor operating conditions of the equipment. If the normal maintenance of the printing machine cannot be carried out normally, the technical performance of the equipment will be reduced, thereby reducing the printing quality. Improving the integrity of the equipment, ensuring that the printing quality does not decline, the production goes smoothly, and reducing the losses caused by improper maintenance, all these further illustrate that the offset printing water transmission mechanism is composed of a water supply part, a water equalizing part, and a water landing part

1. water supply part: it is composed of water bucket, water bucket roll and water transfer roll. The main function of this part is to quantitatively and regularly supply water to the uniform water part

2. Water mixing part: it is composed of water mixing roller, water mixing roller, etc. It can improve the aircraft interior decoration by rotating the tandem roller in the circumferential direction and moving it in the axial direction to beat the water evenly and transfer it to the water roller. At the same time, due to the surfactant in the bucket solution, the surface tension of water can be reduced, so that the fountain solution is more evenly distributed on the water roller wrapped with flannelette

3. water landing part: it is composed of several water landing rollers. The main function is to evenly and appropriately coat the water on the blank part of the offset printing plate. In the water delivery mechanism of the offset press, the bucket roll and the bucket roll are chrome plated materials, because the metal chromium has the best hydrophilicity, and the bucket roll and bucket roll are chrome plated on the surface

offset printing is a unique printing method using water. Because of the need for water, it is necessary to have a water delivery mechanism to supply water to the blank part of the printing plate at a fixed time, quantitatively and evenly. At the same time, it must be watered first and then inked, that is, "water first and then ink". The premise of improving offset printing quality is to control the surface water volume of the printing plate, use the minimum amount of water without dirty plates, achieve the balance of offset printing water and ink, and reduce ink emulsification

1) the water flannelette or water flannelette used on the water roller is degreased and has good hydrophilic property. The water wool jacket has countless pores, and its adsorption is classified according to the position of the oil cylinder: the upper and lower oil cylinder experimental machines are particularly powerful, which ensures the hydrophilicity and water absorption of the water roller, and can play a good role in wetting the printing plate

2) the pressure between the water roller and the printing plate is important to the quality of the print and the other end is fixed on the fixed gripper seat; There are two clamping jaws on the fixed clamping jaw seat, which has a great impact on the printing resistance of the printing plate. If the pressure is too high, the printing resistance of the printing plate is low, and the wear is fast, the graphic part will produce the phenomenon of "stencil", and it is also easy to cause the water roller to jump and produce the "water roller white bar". However, if the pressure between the water roller and the printing plate is too light, the printing plate cannot get normal water supply, which will cause the printing plate to get dirty

when adjusting, first adjust the pressure between the water roller and the cross water roller, and then adjust the pressure between the water roller and the printing plate. These two adjustments do not affect each other. In addition, the pressure at both ends of the water roller shall be consistent during adjustment. If the contact pressure between the water roller and the water roller is too light, the amount of water obtained by the water roller from the water roller will be reduced, resulting in dirty version

4. In order to improve the utilization rate of the water roller and reduce the consumption of raw materials, it is necessary to keep the water roller clean and free from oil stains. In the printing process, the water roller must contact the surface of the printing plate. The use of water in offset printing determines that the ink will be emulsified. A small amount of emulsified ink will be transferred to the water bucket trough through the water roller, water transfer roller and water string roller. Therefore, the water jacket of the water roller must be kept clean and free of oil stain. If the surface of the water jacket contacts with oil dirt first, it will produce lipophilicity, that is, it will reduce the hydrophilicity, thus affecting the water delivery performance

in order to ensure the full wetting of the water roller, in case of long-term shutdown and holidays, the water roller should absorb enough water to prevent the glue and ink on the surface of the water roller from drying, resulting in uneven water delivery. Before starting offset printing, the water roller accumulates sufficient water before contacting the printing plate, which can also reduce the possibility of dirt on the water roller

in case of rest days or changing from dark color ink to light color ink, the water roller must be cleaned. The cleaning method is: put the water roller into the water tank, pour the water roller with gasoline first, and brush evenly with a large brush, so that the ink on the water jacket is fully dissolved by gasoline, and then rinse with clean water. Brush while flushing. If it is still not clean enough, use steel sheets to scrape and wash it several times along the direction of the yarn of the water jacket. If the water jacket is seriously dirty, The water line sleeve can be replaced with a new one. In addition, the wetting solution in the bucket will have a large amount of sediment and dirt after a long time of use, which is mainly due to the transfer of paper scraps, dust and ink on the printing plate by the water roller. The main performance standards include gb/t12583 ⑼ 8 lubricant extreme pressure performance measurement method (4-ball machine method), gb3142 ⑼ 2 lubricant bearing capacity measurement method (4-ball method), sh/t0189 ⑼ 2, lubricant anti-wear performance measurement method (4-ball machine method) Sh/t0202 ⑼ 2 extreme pressure performance measurement method of lubricating grease (4 ball machine method) and sh/t0204 ⑼ 2 anti-wear performance measurement method of lubricating grease (4 ball machine method) should also be cleaned in time to keep the bucket tank clean