Rotary printing press is a type of offset printing press and is often used for printing advertisements, magazines and newspapers. As a large-scale equipment, the rotary printing press is also expensive. Therefore, we should pay extra attention when purchasing and choose products from well-known brands. Let’s take a look at the relevant knowledge of rotary printing presses.
Rotary printing press brand
1. Zhongte
Zhongte Company is a professional development and production enterprise of printing equipment. It belongs to the national high-tech innovation One of the company's projects, it introduces advanced production technology from abroad, while striving for independent innovation and scientific research to create a top national brand. Zhongte Enterprise has more than ten independent patents and has won many provincial and national innovation awards. It has also developed a new generation of intermittent and rotary dual-use printing presses, which have been unanimously recognized by users.
2. Goss
The development history of Goss Enterprises is not too long, and it is currently the largest Sino-foreign joint venture in this industry in China. Facing the growing requirements of users, Goss adheres to the concept of excellence and provides high-quality diversified products, covering commercial rotary printing presses, newspaper rotary printing presses, etc. Each product is a first-class leading product in this category. .
3. Hamada
Hamada has been established for twenty years. It has continuously introduced advanced equipment and technology from neighboring Japan and developed it into a Equipment adapted to China's national conditions meets the current high-speed, multi-color printing requirements. At the same time, Hamada also provides users with complete and high-quality services, proactively meets users' relevant needs, and has established a good reputation in the industry.
4. Beiren
Beiren Group was founded in 1952. Over the past sixty years, it has gradually developed into a well-known printing equipment company at home and abroad. Beiren is a very creative enterprise. It currently has more than ten patented technologies and is at the leading level in the country. At the same time, its high-quality international procurement model also ensures the excellent quality of its printing press products.
5. China Eastern Airlines
China Eastern Airlines’ production line starts from the research and development of equipment to subsequent high-quality sales and after-sales services. It has a comprehensive and complete service chain to provide consumers with Trustworthy products and services. At present, China Eastern Company has a professional production team, superior production conditions, and nearly 40 patented technologies, and can produce thousands of various printing equipment every year. China Eastern Airlines has been working hard towards the goal of "high-quality printing machine supplier" and has achieved good results in recent years, filling the current gap in the domestic printing industry.
Reasons for blurry patterns in rotary printing machines
1. The mesh pits are large and not deep enough. The inner walls of the mesh holes are not smooth and hairy. The chrome plating is thick and the chrome blocks have been filled. Full mesh holes, poor polishing and burrs can cause the ink layer to dry quickly and cause plate blocking. The engraving on the printing plate is too shallow or the dots are not clear. Intaglio is obtained by engraving dots on the copper surface and then chrome plating and polishing.
2. The ink is crusted due to poor storage. Paper blocks, plastic scraps and surrounding dust during printing are adsorbed into the ink due to static electricity, or fall directly into the printing plate mesh, which can also cause paste. ; The machine is stopped during the printing process, and the ink film remaining on the layout has not been cleaned in time, blocking the dots; the ink drying speed is too fast, causing the ink to dry up in the cells. The fluidity of the ink is poor, different types of incompatible inks are mixed in, solvents are misused, and the amount of real solvent in the ink is reduced, resulting in poor resolubility and high viscosity, making it difficult to scrape off non-pattern parts, especially at the edges of dots. It is dry and constantly expanding, and the cleaning is not timely, resulting in the outlets being buried.
3. The pattern cells have long been blocked by dry agglomerates, and the new ink cannot be completely re-dissolved. It piles up on a large area on the printed matter, and the pattern text is smeared; the printing machine speed is too slow and the scraper removes it. After inking the non-pattern parts, the ink has become dry and solid and will not transfer before reaching the imprinting point. The general transfer rate of ink in printing screen holes is 2/3, which means that 1/3 is left on the printing plate. The ink has high viscosity and dries quickly. Even if the roller is re-entered into the ink tank, it will be difficult to dissolve it all. , repeated many times, the ink transfer rate decreases and eventually becomes blocked.
What to do if there is a folding failure in the rotary printing press
(1) Skew, mainly divided into two types: regular skew and irregular skew.
For regular skew, if the three folds are not on the same fold line, one side is on the fold line and the other side is on the left or right side of the fold line, the measures that should be taken are as follows
①Adjust both sides of the folding knife The pressure of the elastic gasket ensures that the force on both sides of the signature is balanced before folding;
②Adjust the pressure of the brushes on both sides of the folding knife, check the wear of the brushes, and replace them if necessary;
③ Check the wear of the bite knife, bite knife back and plug knife. If the folds are skewed due to wear and tear, they must be replaced in time. When replacing a new folding knife, make sure that the highest point where the folding knife and the biting knife meet is ≤3.5mm and ≥2.5mm. In addition, it is also necessary to ensure that each folding knife is consistent. When the folding knife and the bite knife are handed over, there is a 1mm gap between the folding knife and the bite knife back. When replacing the new bite knife and the bite knife back, the bite force between the two It will be too tight. At this time, the bite force between the two needs to be adjusted appropriately, so that the bite knife and the bite knife back have a longer service life.
For irregular skew
① Check whether the wire strap is damaged and replace it if necessary. When welding the wire strap, the interface must follow the direction of the signature. In addition, Check whether the tension of the upper and lower straps is consistent;
② Check the silicone oil concentration. When printing light-coated paper and coated paper, the silicone oil concentration should be controlled to a small point (usually 10:1). When using low-quantity cold-set paper or overpressure paper, the silicone oil concentration should be controlled to be appropriately high.
(2) After cutting the signatures from the newspaper page, one of the inner and outer folds is good and the other is bad.
The measures that should be taken are: adjust the pressure of the paper pinch roller and the direction of the paper guide roller.
(3) Paper with a large basis weight will appear "eight-shaped wrinkles" after folding.
The measures that should be taken are: set up a ventilation knife to remove the gas generated during folding in time.
(4) The eye of the needle is damaged when picking it up.
The main reason for this problem is that the picking needle did not retract in time during the folding process. At this time, it is necessary to adjust the retraction time of the pick needle. Special attention should be paid to the fact that the retraction time of the pick needle must be very accurate. If the time is too long, the paper will be torn. If the time is too short, the paper will lose control within a period of time, which will affect the quality of the paper. Folding accuracy.
(5) When printing low-weight light-coated paper, the innermost paper of the signature cracked.
Main reasons
① The printing drying temperature is too high, which causes the paper to lose moisture and become brittle.
② The pressure of the nip roller is too high when folding, causing the paper to crack or even break.
Measures to be taken
① When printing, set the printing speed and drying temperature to the best matching value, and use the lowest drying temperature while ensuring that the ink is dry; < /p>
② Reduce the pressure appropriately when folding;
③ Install a folding auxiliary glue spray (water) device on the offset printing machine to moisturize and soften the creases of the inner paper.