In printing, the use of dusting is to prevent the back of the product from getting dirty. At present, many advanced printing equipment have eliminated the powder spraying device and adopted three groups of drying methods, namely: two groups of infrared and one group of ultraviolet. At present, most of the printing equipment in our country are infrared or powder spraying devices.
Usually when the ink layer is thick and the dark area is large in production, the printing operator always wants to increase the amount of powder, so that the product will not be scrapped because of the dirty back, but often ignore the amount of powder. This problem may be small. In fact, too much powder will bring a lot of harm.
1. The amount of powder is too large. In front and back printing, the amount of powder on the front side is too large, which will directly affect the shift output when printing on the back side. In severe cases, the blanket needs to be cleaned every few hundred sheets. The product will also suffer from ink color instability, affecting both quality and output.
2. Too much powder affects the gloss of the product. When printing some high-end products, operators always want the ink color saturation to be higher. In this way, the printed product is both bright and bright, and at the same time, the amount of powder is increased to prevent smudging. The powder spray is absorbed by the ink on the ink layer that has not been dried, and will form a layer of mist on the color, which reduces the gloss of the product.
3. The amount of powder is too large, which causes serious wear on the equipment. While spraying powder to the product during production, a considerable part of the powder quantity is flying to the machine's collection chain, gripper and roller. Although there is maintenance time every week, it may not be able to clean up all the dust, and it will inevitably increase the wear on the machine over time.
4. If the amount of powder is too large, it will have a certain impact on the health of the operator. Although the sellers all said that powder spraying is harmless to the human body, the operator stays in the workshop with fine dust every day, and the lungs do not know how much dust to inhale.
5. If the amount of powder is too large, it will also affect the subsequent processing, such as glazing.
Therefore, in the production, we should pay enough attention to the amount of powder spraying, spray as little or as little as possible to achieve the purpose of controlling the back dirt. There are many factors that cause dirt on the back of the production, the key is how to effectively control.
1. Strictly control the density value. The value of each color density is obtained by sampling and observing its K value, dot expansion value and ink color saturation to select the best value. In another sense, the best value (density) obtained by this method is also the best amount of paper to withstand the amount of ink. For example, the best density values ​​we obtained with 128 grams of Japanese coated paper are yellow 1.05, red 1.35, blue 1.45, and black 1.70. We can keep this data for printing in production. Under normal circumstances, it is impossible to get dirty. Adding a small amount of powder will be more safe. But the density is too great, even if the ink layer is not thick, it will still smear. For example, 100% overprint of yellow and magenta and four-color dark overprint, obviously 100% ink layer of yellow and magenta are not thick, if the yellow density value is increased by more than 1.30, the magenta density value is increased by more than 1.50, Exceeding the critical value of the amount of ink the paper withstands, the product is very likely to get dirty on the back.
2. The reason why we use powder coating is because the dark area of ​​the product is large and the ink layer is thick. When encountering such manuscripts, on the premise of not losing the importance of the dark tone of the manuscript, we should make use of the plate-making method and adopt the method of background color removal to make the dark tone ink layer thin. The ink volume is controlled between 235% and 270%, which is 125% to 90% less than the traditional method, so that the density requirements of the dark tone can be guaranteed, and the middle darkness will not be affected due to the excessive ink reduction. Adjust the level. According to relevant data, the total ink volume is 235% and the total ink volume is 360%, the ink volume is reduced by 125%, and the displayed density value is basically similar. When the actual total amount of dark tone ink is 235%, printing can control the back side smudge without spraying or a small amount of spraying.
3. The proof is the customer's certificate and the basis for printing. If there is too much discrepancy between the printed product and the sample, the customer will refuse to accept it without any ado. The question is whether the sample truly reflects the original. For example, there is not such a thick ink layer on the original. In order to achieve user satisfaction when proofing or signing, the amount of ink is desperately increased. This will cause the dots to expand seriously. The dots expand from the center to the surroundings. The ink in the center will definitely exceed the amount the paper bears. It is difficult to avoid smudging without increasing the amount of powder.
4. Ink emulsification will seriously affect the drying time of the product. When the ink contains a certain amount of acidic aqueous solution, it will prolong the time of oxidative conjunctiva on the surface of the imprint, resulting in slow drying and easily causing backside smearing. There are many factors that cause serious emulsification of ink, but the most important thing is water, and at the same time, the amount of ink must be well controlled. When reaching a certain density value, the least amount of ink and the least amount of water should be used. This is the best way to control the serious emulsification of ink.
5. The printing pressure is too light, so that the ink can not be transferred normally. The ink transferred to the paper cannot be well combined with the paper. The ink only floats on the surface of the paper, which is very weak and will cause the back to be smudged. Therefore, within the normal range of dot expansion, the printing pressure should be increased appropriately.
In summary, we have to use less or no powder spraying to control the back side of the dirt, we must start from the manuscript to carry out serious process research, formulate effective process construction plan, through plate making means to produce the original plate and Standard proofs. In printing, we must strictly follow the data operation, control the density value, pressure and water-ink balance of each color, maintain a certain printing speed, appropriately increase some dry oil, and reduce the height of semi-finished products.
Author unit: Henan Post and Telecommunication Printing Factory
Hotel chairs refer to seats used in hotel rooms, lobbies, restaurants, conference rooms, and other places. According to different functions and design styles, hotel chairs can be divided into multiple categories. Below, we will classify and introduce materials and design styles.
1. Material classification:
(1) Wooden chairs: Wooden chairs are one of the most common hotel chairs, commonly used wood including oak, beech, elm, etc. Wooden chairs have a natural and warm texture, making them suitable for use in high-end hotel rooms and lobbies.
(2) Metal chairs: Metal chairs are generally made of metal materials such as iron and aluminum, which are sturdy, durable, and stylish. They are suitable for use in hotel restaurants and meeting rooms.
(3) Plastic chairs: Plastic chairs are usually made of materials such as polypropylene, which are lightweight and easy to clean, making them suitable for use in budget hotels and outdoor spaces.
(4) Fabric chair: Fabric chairs are generally made of fabric or leather materials, with a comfortable texture, suitable for use in high-end hotel rooms and leisure areas.
2. Design style classification:
(1) Modern style: Modern style hotel chairs are designed with simple and smooth lines, emphasizing functionality and comfort. Commonly used materials include metal, plastic, and leather.
(2) Classical style: The design of hotel chairs in classical style emphasizes details and decoration, with commonly used materials such as wood and fabric, giving a sense of elegance and luxury.
Summary: Hotel chairs are classified based on material and design style, and different classifications are applicable to different places and needs. In the interior design of hotels, selecting appropriate hotel chairs can enhance guests' comfort and experience, while also coordinating with the overall design style to create a unique hotel atmosphere.
Wedding Chair,Throne Chair,Church Chair,Nordic Chair
Foshan Shengshi Zhihui Technology Co., Ltd. , https://www.officer-furniture.com