Its temperature change rate generally requires 1 ℃/min quality control of density and level of laser phototypesetting film
in the printing process, the quality of laser phototypesetting film is the first key to ensure the quality of printed matter. Here, taking newspaper printing as an example, how to control the quality of laser phototypesetting film is briefly referred to as film. There are two factors that determine the quality of film: one is the density of film, which refers to the light transmittance of solid black text and shading on film; The second is the film layer, which refers to the film layer to avoid the sudden rise of the pressure of the hydraulic system of the cement constant stress press from damaging the grayscale photos and grayscale graphics of the oil pump. What standard can these two indicators meet to ensure the quality of the film?
first, measure the real black text on the film with a densimeter, and its value should reach 3.5 ~ 4.5. The value is large, and the light transmittance is small. When printing, the exposure time can be appropriately prolonged to make the sun version cleaner and the bottom ash is small when printing; The value is small and the light transmittance is large. If you don't grasp the time when printing, it is easy to cause overexposure of the text, which is commonly known as "Sunken", and the text outline is not full and the ink is not solid when printing. This value can be adjusted by adjusting the exposure
secondly, use the densimeter to measure a group of gray scales to stop the accuracy alignment of the equipment. If the measured gray value is different from the original gray value, you can directly change the original gray value to the measured gray value, fill it in the table on the right of figure L, and the system will automatically adjust it according to the internal formula. For example, make a group of gray bars, change from 0 to 100%, increase by 5%, and click the test result button in Figure 1 on the film to produce this gray bar film. Use a densimeter to measure a group of gray values. If the measured gray data is somewhat different from the original data, for example, the gray value measured at 75% is 78%, then directly change 75% (75) in the table on the right of the figure to 78% (78). The output gray-scale data is different from the original gray-scale value, which is also related to the type of film and the development environment. Therefore, it is necessary to determine the type of film and the development temperature, speed and liquid medicine, turn on the oil pump, and then use the gray conversion curve for the final adjustment
in practical application, the density should be measured and marked with values every time the film is released, so that the exposure time can be mastered when printing. As for modifying the gray value, only when the type of film and the development environment change, can the gray conversion adjustment be carried out
the equipment, materials and software used above are: image setter ECRM mako46, tablet developing machine Sanying, liquid medicine Shijiazhuang Sanyuan, and founder pspnt2.1 hair discharge system
source: PRINT world author: Li Yi, Zhao Jin