Quantitative ink supply system for the most popula

Quantitative ink supply system for flexographic printing people engaged in flexographic printing know that quantitative ink supply system is one of the important factors affecting the final printing quality and printing effect

many people compare the ceramic roller, the main component of the quantitative ink supply system, to the heart of a flexographic press, and the doctor blade, another important component of the quantitative ink supply system, to the valve of the heart, which effectively controls the amount of ink entering the heart. The role of the two in the ink supply system is clear at a glance, and the status and importance of the entire ink supply system in the printing machine is self-evident

development overview of ink supply system

1 Two roller system

generally, the quantitative ink supply of flexographic printing press is completed by two rollers, which is called two roller system for short. After inking from the ink tray, another rubber inking roller scrapes the ink, and then the inking roller transfers the ink retained in the hole to the printing plate to complete the whole process of ink transfer. The two roller system can realize the quantitative ink supply in a certain program. At present, this structure is still widely used. The main technical indicators must meet the requirements of relevant method standards for cement pressure testing machines. When users select pressure testing machines, they are used in medium and low-grade flexographic printing machines, coating machines and carton printing machines. Such a structure is suitable for occasions where printing and coating quality requirements are not high

2. Forward scraper system

when the control of ink quantity requires more accuracy, this two roll system will have problems. Especially when the press speed reaches or exceeds 100m/min, the hydraulic pressure generated by the high-speed flow of ink between the embossing roller and the ink scraping roller tends to increase the gap between the two rollers, resulting in the transfer of excess ink to the printing plate and substrate materials. Considering the above problems and the requirements of accurate ink supply, people first proposed a quantitative ink supply system with different elastic modulus for bending and stretching of forward scraper type plexiglass materials, which is similar to gravure printing system. In this system, the rubber inking roller transfers the ink belt from the ink tray to the embossing roller, then the scraper scrapes the ink not deposited in the hole from the surface of the embossing roller, and transfers the ink in the hole to the printing plate, realizing the function of quantitative ink supply

corrugated metal roller can be used, but it has a large investment range, high scientific and technological content, broad market prospect and short service life. The ink supply system combined with the scraper should use the ceramic corrugated roller as the metering roller. The scraper is usually made of steel, with its back against the metal pad and a pressing plate. After it is installed on the metal support, the support provides appropriate scraper working angle and pressure

the so-called working angle is the included angle between the scraper and the tangent of the contact point. For the forward scraper, this angle is usually between 55 and 60. Like the two roller system, when the printing machine speed is higher than 100m/min, the scraper and the embossing roller in this system will also be subject to the effect of hydraulic pressure, which tends to separate the two, resulting in more ink transferred to the printing plate and substrate materials. For the fine printing, such a result is obviously not allowed

3. Reverse scraper system

the quantitative ink supply system with reverse scraper structure can solve this problem. The only difference between the system and the forward scraper system is the scraper position and its working angle. In general, this angle is between 30 and 35. Some manufacturers also design it to be up and down 40. The reverse scraper system does not have the function of lifting the knife by hydraulic pressure, so the printer can work at a higher running speed

4. The fully sealed double scraper cavity ink bucket system

reverse scraper structure solves the problems arising from the high-speed operation of flexo printing machine. However, whether the reverse scraper, the forward scraper or the two roll system, they all belong to the open ink supply structure, and the ink source is stored by the ink tray. Some of the ink on the upper ink roller belt is used for printing and the rest is returned to the ink tray after a certain process of good transportation and packaging

such a structure makes the ink frequently and directly exposed to the atmosphere in a large area. For solvent based ink, the solvent will volatilize into the surrounding air, resulting in changes in ink characteristics and environmental problems; For water-based inks will also produce bubbles, and ultimately affect the printing quality

the fully sealed double scraper cavity ink bucket system is composed of corrugated rollers (usually ceramic corrugated rollers), two scrapers, sealing strips, ink storage containers, ink pumps, ink delivery hoses and other components

the characteristics of the system can be based on the following: the reverse scraper structure is adopted in the quantitative ink supply system, so the printer can work at high speed; It reduces the volatilization of solvent in the system when using solvent based ink, and alleviates the problem of environmental pollution; The problem of foam in the process of using water-based ink was stopped; The rubber inking roller used for mining in the common structure is excluded; The system can be quickly connected with the cleaning system to completely clean the ink stained components in the system in a short time, reducing the ink color change time. It can be directly cleaned inside the ink supply sealing system with a pump and detergent without removing the rollers and other ink stained parts, which is conducive to reducing downtime and giving full play to the production capacity of the machine