Restrictions on Printing Quality of Newspapers

Reading newspapers has become an integral part of modern life. People have read newspapers more from purely for information to enjoying life. The printing quality of newspapers has become relevant to every modern D life. Therefore, continuously improving the printing quality of newspapers is the responsibility of newspaper printers and an eternal theme in the development of newspaper printing. Although the printing quality of our country’s newspapers has greatly improved, problems such as often inaccurate colors, heavy ink odors, and black and white layouts are still prevalent. Among these, more is due to the printing of newspapers in our country. Material level constraints.

First, printing quality

In the past decade or so, the introduction of a large number of international-level printing presses and the continuous improvement of prepress technology have made the quality of Chinese newspapers significantly higher than they were just a few years ago. The registrations are good, the color is much more accurate, and the paper is much better. Newspaper printing quality is a key factor used by newspapers to attract readers and increase market share. It is also an important competitive performance of printing companies. Advertising income is the pillar of the development of the newspaper industry. The continuous improvement of the advertising quality of the advertising customers for color advertising and the improvement of the level of readers' appreciation have also led the newspapers to pay more and more attention to the printing quality of newspapers.

Under the conditions that production equipment has basically been satisfied, people have gradually realized the impact of printed materials on newspaper quality. To improve the printing quality of newspapers, in addition to equipment, nothing more than the role of the two most direct: First, strengthen the management of process quality, and continuously improve the management level. Many newspaper printing companies have set up specialized quality departments, and they are effective in data control and standardization of quality control. The second is to improve the grade and quality of raw materials. The rapid development of newspaper printing, and China's printing material development speed has not fully followed, the development of printing materials lags behind the printing technology level. We have realized that under the premise of relatively stable printing equipment, printing materials are the most important factor restricting the printing quality. With good quality raw materials, the printing quality will be significantly improved, and there will be much fewer print failures.

At present, the excessively low price competition of printed materials in China has severely restricted the printing quality of newspapers. This outstanding contradiction requires us to have a comprehensive and correct understanding of printed materials, to distinguish the impact of different materials on the quality of newspapers, and to control them so that they can not only ensure the stability of product quality, but also increase the cost.

Second, the material on the print quality constraints

Paper

Paper is the carrier of newspapers and is the main raw material for newspaper printing. The quality of the paper affects the final quality of the printed product. On the one hand, the paper's physical properties such as smoothness, whiteness, tensile strength, and ink absorption performance directly affect the printing quality of newspapers. Smoothness is the primary condition for ensuring print quality. Poor smoothness, insufficient ink transfer, blurred imprinting, and even partial imprinting. The whiteness of the paper is high and the contrast of the image is strong. The closer the image is to the quality of the original, the wider the level of performance. The higher the tensile strength of the paper, the easier it is to break the paper during printing, which not only guarantees the printing quality, but also avoids the impact of the downtime caused by the paper break on the print quality. The paper's ink absorption performance is good, it can avoid the phenomenon of through-printing or chalking, ensure the drying speed of the ink, and improve the glossiness. The moisture content and the two sides of the paper also affect the print quality of newspapers. Falling off the powder, poor ink drying speed, finished wrinkles, and unstable registration all affect the printing quality.

With the development of China's paper industry in recent years, the quality of domestic newsprint has been greatly improved, and the degree of guarantee for printing quality has also been greatly improved. At present, there are mainly two issues that affect the overall quality of newspapers. First, the importance of the paper replacement on the quality of the same newspaper is not enough. Not only does the phenomenon of alternating use of paper by different manufacturers often occur in the printing process, it has a great influence on color reproduction, and often the same newspaper has different stacks. Don't) The paper color and printing quality are inconsistent or even different. Second, when customers, especially customers, supply paper, they place too much emphasis on whiteness in terms of paper requirements, but do not attach importance to more important printability indicators such as ink absorption and smoothness, and think that white paper is printed out. It should be good-looking. In India, it is the quality of the printing factory that causes the printing quality of the same machine to vary greatly. The printing quality is also difficult to guarantee.

2. Ink

The ink problem is a problem that many readers report. If we ask the friends around us, most people will tell you that China’s newspapers are all touched by ink, and the ink tastes unpleasant after opening. In fact, this is mainly an ink problem. Nowadays, the production of newspapers is dominated by domestic inks. There are common problems such as slow drying, poor rubbing resistance, large gray scale, lack of hue accuracy and saturation, and the newspaper cannot be completely dried when it is in the hands of readers. , heavy taste, color and dull, which seriously hampered the overall printing quality of newspapers in our country.

The quality of ink is mainly determined by raw materials and production processes. The price of ink with good materials and advanced processing technology is also high, and printing companies are generally not easy to accept. In the increasingly fierce competition in the ink industry, under the circumstances where each factory competes for price reduction, only low-cost raw materials and simplified processes are used to reduce costs, so that the quality of ink cannot be guaranteed, and the quality of printing is affected. I have heard many times that some friends working in the imported ink business say that the price level of China's newspaper ink is too low, and the price of imported ink is far from its gap, and it cannot enter the Chinese market at all.

The domestic color version of newspapers has now become the mainstream, with increasing emphasis on color quality. The hue accuracy of domestic inks is not good, but at present, most of the standard parameters are used in pre-press separation in China's newspaper industry, which makes the pictures displayed in the printing appear boring, dark, and small in contrast. The color cast problem is also more prominent. To better restore the color of pictures and advertisements, there must be higher color accuracy requirements for the ink. At present, there are certain differences in the hue of the inks produced by different manufacturers in the country. This is mainly because the manufacturing standards of the ink factory have not been unified yet. In the future, with the increasingly perfect color management system in printing plants, ink problems will seriously restrict the normal operation of the color management system.

3. Blanket

The blanket is an intermediate material that is responsible for the task of transferring the ink on the printing plate to the paper, and plays a key role in offset printing. The same brand of blankets that are suitable for rotary cold-fix printing has different model specifications. The price per square meter ranges from 890 to 1,560 yuan, and the gap is more than a few hundred dollars. The good blanket not only has suitable hardness and elasticity, but also has small compression deformation, better ink-transfer performance, better paper-removal performance, and longer life cycle. In this way, the quality of the ink transfer during the printing process is high, the ink color is uniform, and the dots are clear. The effect of blankets on the print quality of newspapers is very direct and can be used for a longer period of time. Therefore, good blanket products should be used as far as possible.

In the newspaper printing field in our country, many newspaper departments and personnel engaged in procurement mainly pay attention to the brand and price of blankets, and often pursue the purchase of the desired brand products at the lowest price. In fact, there are many varieties of blankets used by the same brand to adapt to newspaper rotation, and the quality varies greatly. These differences are mainly reflected in the printability and have a great impact on the reproduction of outlets, not only affecting the service life, but also affecting The quality of the print.

The mounting method of the blanket is also an important factor that affects the printing quality. Most of the newspaper presses introduced in recent years use the T-bar mounting method. This type of card mounting has certain restrictions on the tension of the blanket, and there are many strict requirements on the installation. The installation effect is often not satisfactory when the installation is not good or the new outlet is installed. Now when some imported equipment is imported, the supplier uses the scroll-type card loading method according to the user's requirements (commercial rotary machines use this type of card loading method). Recently, the domestically-made rotary machines have also adopted this method, which is very effective. It not only saves the installation time, but also has outstanding advantages in the use of the blankets and the reduction of outlets. The outlets are clear and neat, and the printing quality is well guaranteed. .

4. Cots

The rubber roller is the main component of ink transmission. The ink on the layout is good and bad, and it is directly related to the rubber roller, which indirectly affects the quality and stability of the printed product. The rubber roller must first have good quality of raw materials, moderate hardness and good elasticity, which is directly related to the quality of the selected raw materials, that is, related to the price of the adhesive. Generally, at least imported rubber compounds should be used. The quality of pure Chinese plastics whose price is lower than 0.12 yuan/cm3 is often difficult to guarantee the use effect. Secondly, it is necessary to pay attention to adjusting and cleaning the rubber rollers in time. After the rubber roller is used for a period of time, the surface will be hardened due to oxidation, and it needs to be thoroughly cleaned to extend the service life of the rubber roller.

The development of the domestic rubber roller industry lags behind that of the printing industry. There is a clear gap between the application of high-tech materials and the processing technology of the rubber rollers. Due to the low barriers to entry, there are many companies engaged in this industry. We all know that imported brand rubber rollers are of good quality, but printers rarely use imported rubber rollers for cost considerations. There are several types of rubber, such as domestic glue, rubber mix and pure imported glue. The quality varies greatly. The use of a rubber roller with a low price for adhesive is a very important factor restricting the stability of newspaper printing production. The choice of roller should be compatible with the printing equipment and the printing quality requirements of the product. Select a more formal manufacturers, use a better price of some of the better rubber compound, the cost will not increase much, but the product quality has a great guarantee.

5. Fountain solution

China's newspaper printing has a large area of ​​ink, and in order to make the layout clean and convenient for printing, many factory operators are accustomed to increasing water consumption, which is also an important reason for the newspaper's hue of inaccuracy and slow drying of printing ink. Therefore, the influence of the fountain solution on the printing quality must be taken seriously. The effects of the fountain solution on the printing quality mainly include the following aspects: The panel can be quickly cleaned, the dampening solution is used to moisten the printing plate, the pH value is kept stable, the printing plate is resistant to the printing force, and the ink drying performance is improved. It can be said that the use of fountain solution plays an important role in improving the quality of offset printing.

The largest relationship with the fountain solution is the ink, and its chemical composition is directly related to the effect of the fountain solution. As mentioned earlier, due to the low price of ink in China and the unstable composition of inks, there is no absolute solution for all kinds of domestic and imported fountain solutions on the market. However, some imported lubricants The relative time for the study of the liquid is longer and the printability will be better. During use, it is necessary to notice the hardness of the water and the concentration of the fountain solution. Try to use demineralized water and control the proper ratio of addition.

From the printing point of view, to control the final quality of the newspaper, ensure that the ink is drying faster, reduce dot gain, and minimize the amount of fountain solution is a key factor. Therefore, it is necessary to spend some time on the selection and use control of the fountain solution to find out the best solution.

6. Plate

The plate is an intermediate consumable material for printing. It does not directly relate to the reader, but it is the intermediate carrier for the transfer of dots and has a direct influence on the printing quality. PS version of the production process has been relatively mature, as long as the use of reasonable quality control methods, easier to ensure quality. However, there are also some minor problems. For example, the high rate of Internet point loss, de-inking, and dirty spots are all directly related to the printing media. They often appear during printing, and sometimes they may have to be changed. At present, the PS version used in the newspaper industry is mainly domestically produced, and the brand is also relatively large. In terms of quality, the difference is not so great. It can basically meet the needs of printing. The main differences are the printing time and the resistance to printing force. Plates with fast exposure time are good for ensuring the timeliness of newspaper publication, but the tolerance for exposure will be smaller and need to be carefully controlled. With the maturity of CTP technology, the price of CTP plates continues to drop