Determinants and maintenance points of printing qu

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The determinants and maintenance points of the printing quality of the plate printer

the plate printer is one of the essential equipment for offset printing. The printing quality of the plate printer mainly depends on the following two factors:

1 Whether the vacuum pumping system of the plate printer works normally. Whether the film surface and sulfuric acid paper carbon powder surface are closely matched with the photosensitive film surface of other printing plates of PS plate

2. When gallium iodide lamp, xenon lamp, purple fluorescent tube and other light sources are exposed, whether the illumination on the whole panel is uniform, and whether the illumination in the middle and around is consistent and uniform is the standard to measure the performance and quality of the printer. The most common fault of the offset vacuum printer is that the film surface of the film, the carbon powder surface of the sulfuric acid paper and the photosensitive film surface of the PS version are not closely matched enough, and the air pumping is not solid and leaks. The occurrence of this fault will seriously affect the printing quality. Because the vacuum pumping can not reach a certain vacuum degree, the air leakage phenomenon is serious, especially for the electric four-color film with the drying line. If the pumping is not solid, the drug film surface of the film cannot be closely absorbed and matched with the PS version photosensitive film, and the small dots, thin lines and fine layers of the PS version will be lost. The main reason is that the pressure of the accumulator must be guaranteed to be in the normal task state. There is a gap between the film surface and the photosensitive film of the PS version, which is not compact and solid. During exposure, the void of the image and text points of the PS version is tilted, and it cannot be close to the photosensitive film of the PS version. If the gallium iodide lamp is exposed from above, the photosensitive film of the void will be decomposed by light after exposure, and then after the automatic and manual development process of the PS version, Weak points and pictures in the void contact will be lost. At present, various experimental specifications generally require that the accuracy of parameter testing should not be less than 1/3 of the allowable error of experimental conditions

in addition, the plate printer, like other printing equipment, must be properly maintained frequently in order to be in good working condition for a long time. Therefore, the following points need to be done:

① maintain the integrity of the function of the air extraction system. The vacuum pump should be checked once a week. The vacuum oil level should always be aligned with the oil level line. All oil must be replaced after one year of operation

② wipe and moisten the frame of the blanket with glycerin once a week. When the machine is not in use, cover the blanket on the glass table with a cloth curtain to prevent dust and debris from entering

③ the surface of the glass plate table must be kept clean. When wiping, first clean it with a soft brush, and then wipe it with degreasing gauze and anhydrous alcohol

④ the lamp curtain, which is used to block the scattered ultraviolet light and avoid the sun exposure to human skin and eyes, is composed of two layers of cloth, which is white polyester cloth, which plays the role of reflecting light. The outer youth friends are covered with a layer of red velour cloth to block ultraviolet rays. The inner layer will affect the effect of reflecting ultraviolet light due to yellowing over time, dust, oil and dirt, etc., resulting in an increase in exposure time. At this time, it is best to replace a layer of white polyester. The voice of the industry for the formulation of thermal insulation material standards is also rising

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