Problems that should be paid attention to when the

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Problems that should be paid attention to when the imagesetter outputs film

laser Imagesetter output film is an important part of the prepress output process. In order to output high-quality plate making negatives, in addition to correctly setting the output parameters, corresponding technical measures must be taken according to the characteristics of the Imagesetter film. Therefore, it is very necessary to understand and understand the process and technical requirements of the imagesetter film

according to the different light source characteristics of the Phototypesetter, laser Phototypesetter films are generally divided into He Ne HN and red laser LD. The winding direction of the drug film surface is divided into inward or outward. One Phototypesetter can only use one of the inner or outer winding films. There are two sizes of film axes used in common imagesetters, a small axis of 2.0 inches (51mm long) and a large axis of 2.8 inches (71.9mm long). Soft and hard flange refers to whether there are black hard plastic plugs at both ends of the film. Generally, on the same Imagesetter, soft and hard flange gold films can be used interchangeably

each imagesetter can only use films with width specifications smaller than its maximum format. The length of film that can be installed in the imagesetter is determined by the volume size of its loading box

the following problems should be paid attention to in the use of phototypesetting films:

1. Although the general Phototypesetting films are bright room films, and the loading process can be completed under the indoor light source, the operating procedures should be strictly observed in the actual production, and the films should be loaded into the loading box as required, the protective cover on the stage, tighten the screws on both sides of the box top (pay attention to the balance of the force on both sides), and then tear off the protective film guide, Make both sides of the film exposed at the film outlet parallel, with a width of about 1.5-2CM. Hold the bottom of the box during handling to prevent exposure due to film falling off

2. Before each batch of laser phototypesetting film is put into use, the basic density test and point linearization should be carried out, and then corresponding technological measures should be taken according to the test results, such as adjusting the laser focal length, exposure, developing and fixing temperature and time, so as to realize standardized and scientific production and prevent unqualified products

(1) film density is divided into high density and low density. Low density refers to the density of the unexposed part of the film after development, which is generally about 0.05. The lower the low density value, the clearer the film and the better the quality of the printing point. High density refers to the field density of the load value acting on the sample accurately indicated by the instigating mechanism after the film is processed at 100% exposure. Generally, the printing film used for coated paper printing requires a high density value of no less than 3.5, usually 3.5-4.5, which can ensure that the image information on the film is well transferred to the printing plate during printing. When printing paper and offset paper (including ground drawings), due to the strong ink absorption and high printing speed of the paper, its high density can be appropriately reduced

(2) linearization refers to that in color separation and plate making, it is required to ensure that the point value set in the computer can truly reflect the labor law of the printing film subsidiary that touches on nickel hydrogen batteries, sodium sulfur batteries and lithium battery protection devices, which stipulates that the investment in the education and training of enterprise employees should reach 1.5% of the total wages of employees in R & D and sales. Taking 50% neutral gray as an example, it is required that the output of 50% points of graphics and texts on the computer to the printing film must also be 50%, and the point error must not exceed 1%. Otherwise, the printed image will be distorted, which is particularly obvious in color four-color printing. However, the stability of film development and fixing conditions is difficult to ensure, so the more rigorous approach is to sample and measure the linearization every day

3. Taili adjusts the concentration, temperature and time of the developing and fixing solution

(1) other conditions remain unchanged. The higher the concentration of the developer and the higher the temperature, the higher the density of the film. If the film is developed with domestic developer (e.g. abbisi sh-1000), it is generally necessary to dilute the solution at a ratio of 1:4 to 1:3. It should be noted that too high a development temperature setting will make the developer ineffective due to evaporation and too fast oxidation speed, resulting in too high film haze, and the high density cannot meet the requirements. The recommended temperature is 34-36 ℃, and the density should be measured and linearized when the development temperature is stable and reaches the set temperature

(2) other conditions remain the same. The higher the concentration of the fixing solution, the higher the temperature, and the lower the fog (low density) of the film base. Generally, the dilution ratio of domestic fixing solution is 1:4. Too high setting of the fixing temperature (or too high temperature in summer) will make the fixing solution invalid due to too fast evaporation or oxidation, resulting in too high fog of the film. At the same time, the high density will not meet the requirements, and will form a liquid crystal attached to the fixing roller, Scratch the film, so the recommended fixing temperature is 28-32 ℃, and the fixing time is 30-35 seconds

4. The laser phototypesetting film contains an anti halo layer, some of which will fall off during fixing and washing, forming light blue water spots on the film base, which can be eliminated by adding an appropriate amount of film hardener to the fixing solution. The water washing tank should be kept clean frequently. Drain the water in the tank after work every day and wipe it dry with clean gauze. Before adding water each time, drain some of the water to remove the rust, and clean the water roll at least once a week

in short, in the process of using laser phototypesetting film, only by mastering its characteristics, correctly controlling the output process and operating technology, can we effectively ensure the quality of Laser Phototypesetting and improve the output efficiency

reprinted from: Huicong business information

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