The influence of the most popular offset printing

2022-08-17
  • Detail

The influence of offset printing speed on printing quality

in addition to the process and materials, the printing speed also plays a certain role. It is necessary for printer operators to be familiar with the relationship between them, especially in modern offset presses. Today, with rapid development, it is particularly necessary

1. The influence of printing speed on printing pressure

in order to make the pictures and texts coated with ink on the printing plate can be clearly transferred to the surface of the substrate, there must be sufficient printing pressure. However, the printing pressure should not be too great, Excessive printing pressure will cause the substrate to continue "NASA's cooperation with the industrial field continues to deform, make the impression thicker, point and level, and paste the plate, which affects the clarity of graphics and texts, and at the same time will aggravate the wear of the printing plate, reducing the printing resistance of the printing plate. When the printing pressure is insufficient, there is no sufficient and reliable contact between the printing plate and the blanket, and the printing mark will become shallow, affecting the clarity of graphics and texts.

when the printing speed increases, the ink color of the impression will become shallow. At first, it was thought that the printing speed increases, printing a The force decreases, but it is not. Because when the printing speed increases, the pressing time decreases, the pressing time on the surface of the printed matter decreases, and the amount of ink transferred to the surface of the substrate also decreases, and the density decreases. As a result, the ink color of the imprint becomes lighter. In actual production, in order to make up for this defect, the method of increasing printing pressure is often used

in addition, under the same impression, the printing speed is also directly related to the size of the press cylinder. In order to obtain the same print quality, the printing speed of the printing machine with large impression cylinder must be slower than that of the printing machine with small impression cylinder

2. Influence of printing speed on paper

as a substrate, paper will produce certain deformation under pressure, mainly elastic deformation and plastic deformation. In modern multi-color high-speed printing machines, the stamping interval between two color groups is very short, only a fraction of a second. In such a short time, the ink of wet press wet overprint cannot be completely dried. In this process, the paper needs to be wetted and embossed for several times, and its surface strength will decline. Therefore, it is required that the water absorption of the printing paper should not be too strong. Otherwise, not only the overprint of 98.07 will be inaccurate due to excessive water absorption of the paper, but also the paper galling will easily occur

practice has proved that when the ink viscosity is certain, the printing speed is the main factor affecting whether the paper will be roughened in the printing process. In general, the faster the printing speed, the more obvious the paper galling phenomenon

3. The influence of printing speed on ink transfer

fundamentally speaking, the process of printing without obvious eccentric brush between its head and counterbore is the process of ink transfer, and the ink is mainly from the surface of the blanket substrate of the ink bucket roller printing plate. In this process, the change of printing speed has a great impact on the ink

the ink is output from the ink bucket and transferred by the ink bucket roller. After countless times of extrusion, shearing and tearing between the ink rollers, it is quickly beaten evenly, and at the same time, a large amount of heat is generated, which increases the ink temperature, reduces the viscosity and enhances the fluidity. The faster the printing speed, the more heat generated, and the higher the ink temperature. If the heat generated cannot be taken away in time, the ink at too high temperature will be a little fuzzy and unclear on the printed matter, and even paste and fly ink will appear, which will seriously affect the quality of the printed matter

4. The influence of printing speed on the printing plate

in a printing cycle, the printing plate should contact and roll with the water roller, inking roller and rubber roller successively. Obviously, the increase of printing speed will have a great impact on the printing plate, thus accelerating the wear of the printing plate, resulting in local loss of points

in short, a good print must be equipment. Comprehensive embodiment of process, technology and many other aspects. In practical work, we should try to avoid frequent acceleration and deceleration, which is not only conducive to ensuring the quality of printed matter

Copyright © 2011 JIN SHI