Check the print frequently
Frequent inspection of printing refers to the constant inspection of product quality during the printing process. In the process of offset printing, there may be various situations that affect the product quality, resulting in a large number of defective or even waste products. Therefore, in the printing operation, it is essential for book printers in china to check the printing sheet frequently.
Frequently check the printing sheet, including the following contents: check whether the overprint is accurate, check the ink color, check the quality of the dot, and check whether there are dirty spots, white spots, paste plates and pattern plates.
Stir ink fountain frequently
Frequent ink mixing refers to the ink mixing in the ink holder at intervals during the printing process. Mixing the ink fountain frequently can ensure continuous underground ink, which is the premise to ensure the uniformity of ink color before and after printing.
Ink is a kind of plastic fluid, which has thixotropic property which changes gradually with the action of external force. In other words, when the temperature of the ink is kept at a certain level, the static ink is stirred with a certain external force, and the ink becomes thinner and softer, and the rheological property is better; when the external force stops stirring, the ink becomes thicker and harder, and the fluidity becomes worse. If the ink hopper is not stirred for a long time, the fluidity of the ink will be poor, resulting in the phenomenon of ink blocking or no inking. It is difficult for the ink roller to transfer ink and even ink. The amount of ink in the printing plate is insufficient, which makes it difficult to break in the middle of the ink, so that the remaining ink layer can protect the layout and cause plate dropping. The ink mixer can be installed in the ink holder to stir the ink evenly to increase the fluidity of the ink. The ink in the ink holder can also be stirred with an ink knife.
Frequently check the page moisture
Frequently check the moisture content of the printing plate refers to constantly checking the moisture content of the printing plate during the printing process. In the process of printing, it is an important premise to correctly master and control the moisture content of the page to achieve the balance of ink and water in the printing process. Identification method of moisture content in the production process:
Visual inspection. In daily production, the operator’s experience is usually used for visual inspection. The method is to use the illuminator to slant the layout, and judge the size of the water content according to the strength of the reflected light of the layout; the thicker the water film, the stronger the reflection light, and the thinner the water film, the weaker the reflection brightness.
According to the print failure phenomenon judgment. If there is paste version, dirty version phenomenon, we should pay attention to whether the water content of the page is too small; if the printed matter appears dull, patterned, curled, uneven paper collection and other phenomena, the page moisture may be too large.
In the printing process, if we can adhere to the “three flat, three frequently, two small” process measures, then book printers in china can stabilize and improve the production and quality of offset printing products.