When selecting printing rollers, we need to inquire in detail about the functions of each roller. Users can easily query the functions of the rubber roller from aspects such as hardness, roughness, and diameter changes. This shows the comprehensive characteristics of the rubber roller, but as many professionals who purchase rubber rollers, they need to carefully investigate its physical and chemical functions before making a decision. Today let's learn about the technical functions of printing rollers together.
1. Physical function
(1) Inclusiveness. The technical function of the printing roller is to carry water and ink, and to be hydrophilic and ink loving, which is influenced by the surface roughness of the roller and the affinity of the particles themselves for water and ink.
(2) Elasticity. It can be displayed by the indentation reflection ability, and the numerical display is the indentation width. A rubber roller with good elasticity can flexibly reflect pressure, and a small given pressure limits the variation of indentation width; But if the elasticity is poor and the pressure increases, the width of the indentation will not change significantly. The latter is unlucky for printing workers who need to adjust their machines. Internationally, printing machine manufacturers will limit the indentation reflection value based on the elasticity of the original rubber roller, making it convenient for users to adjust the line pressure between the rollers. Of course, if the original roller is replaced, the adjustment value needs to be re measured and determined based on the indentation reflection ability of the new roller.
(3) Vibration absorption. Different types of printing machines have different vibration reduction requirements for the technical function of printing rollers. For example, when the drum of a single printing press is in the neutral position, the printed offset paper and copperplate paper are delicate. In order to maintain stability in front of printing, it is required that the rubber rollers of a single printing machine have good vibration reduction performance during printing. On the contrary, high-speed operation generates high heat, and energy needs to be transmitted and stored through rubber rollers, so the rubber rollers used for wheel improvement have low requirements for vibration absorption.
(4) Wear resistance. Users often pay great attention to this because durability means durability, long lifespan, and cost savings. The wear resistance of rubber rollers is indeed very important, as it directly relates to the ability of the rollers to maintain surface area and prevent impurities such as chemicals from corroding, and also supports the inclusiveness of the technical functions of printing rubber rollers. However, it only lacks wear resistance to determine whether a rubber roller can be used in printing.
(5) Voltage resistance. Although soft rubber rollers are more suitable for printing and easier to process, it is necessary to ensure a certain degree of hardness and good organization to enable the rollers to adapt to changes in printing pressure and avoid constant roller and printing quality caused by frequent adjustments by users.
(6) Friction is used to maintain the elasticity of the paper. Especially in printing and newspapers, improper friction on the surface of the printing roller can cause the paper to slip and break.
2. Chemical function
(1) Corrosion resistance. If various chemicals used for printing, such as ink, paper, dampening solution, cleaning agents, etc. Containing some corrosive substances, the rubber roller should have a certain degree of corrosion resistance.
(2) Conductivity. During single sheet printing and paper production, materials such as ink can generate static electricity if they are not suitable. In severe cases, it can form ink rollers and double sheets. Therefore, in addition to some direct influencing factors, the rubber roller also requires anti-static function. However, the electrostatic embossing roller in gravure printing requires quantitative charging under certain conditions.
(3) Heat transfer. Any type of rubber has an upper limit for high temperature resistance, and the high temperature resistance of rubber directly determines the service life of the printing roller's technical function. Especially at present, more and more high-speed newspaper rotary printing machines and commercial rotary printing machines are being used in the industry. Their high speed has reached 60000 rpm, and high-speed operation will inevitably cause high heat. Therefore, it is required that the printing roller has superior heat transfer performance to ensure normal service life and printing quality.
(4) Water delivery accuracy. The water roller should have hydrophilicity and ink repellency. A good water roller should evenly apply water or dampening solution to the surface of the roller, so that the surface faces a certain amount of water. In addition, water rollers using alcohol based dampening solution require a flexible dampening solution. Assuming that the rubber roller only has a good affinity for alcohol with strong wetting properties in the dampening solution, but carries less water, it will inevitably cause a series of printing problems such as paper washing, ink washing, crystallization, excessive emulsification, and narrow water supply restrictions. Therefore, the accuracy of water transfer is crucial for maintaining the balance between ink and washing.
(5) The ability of chemical solvents. If the chemical composition of the rubber roller, cleaning agent, ink, and dampening solution is.
The above is today's introduction to the technical skills of printing rollers. The rubber roller used has a bright color from the appearance, and the surface of the glue is delicate and smooth. The glue is firmly bonded to the adhesive core. The size of the rubber roller will not change significantly at different temperatures, and can adapt to high temperature and high humidity environments or cold and dry climate conditions.
