How to improve the printing durability of the printing plate
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Printing companies to improve the printing durability of printing plates is a key link to reduce raw material consumption, reduce product production costs, shorten production cycle and improve economic efficiency. Anmei Mall analyzes the following methods in practical work to improve the printing durability of the printing plate.
1. Strictly put the printing materials into the warehouse. In particular, you must ensure the purchase of high-quality paper and high-quality PS version. For example, 52g/m2? 60g/m2 book-printing papers printed by the magazines, if the purchasers are eager to buy cheap papers from informal paper manufacturers, the whiteness, uniformity, smoothness, smoothness, surface tension, sizing degree, etc. The technical indicators can not meet the printing requirements. The surface of the paper is rough, the paper is gray, and there are many fine sand grains. This makes it easy to wear the PS resin film, which reduces the printing durability of the printing plate. Therefore, in order to improve the printing durability of offset printing plates, we must first grab the materials from the purchase channel. Unqualified raw and auxiliary materials do not enter the factory and are not included in the warehouse. At present, there are many brands in the printing materials market, which are difficult to distinguish between good and bad. When printing companies purchase materials, they should shop around to ensure quality and purchase high-quality printing materials.
2, to master the correct PS version exposure time. Pay special attention to the amount of exposure, do not over-exposure, so as not to affect the printing durability of the plate. Under normal circumstances, the four-color color separation film requires 3% of the small dots to lose the sun, 98% of the large dots do not paste the version; the pattern, lines, and text are clear, the small graphics are not lost, the text is full and bright, not lacking Pen breaks and so on.
3. The concentration of the developer solution of PS plate should be strictly controlled. When preparing the developer, it should be prepared in strict accordance with the manufacturer's instructions. The developer or developer powder, sodium hydroxide and water should be measured accurately by means of measuring instruments. Do not rely on experience to formulate or dilute the developer. If the exposure is excessive during the printing process, the excessive concentration of the alkaline solution of the PS plate developer or the high water temperature will directly reduce the printing durability of the PS plate.
4. Prevent oxidation of the surface of the plate. When the offset press stops midway or eats and rests in the afternoon, it is necessary to rub the gum arabic to prevent the plate from being exposed to the air for a long time, which causes the plate to oxidize and reduce the printing durability of the plate.
5. Improve the printing durability of the printing plate by baking the PS plate. Nowadays, many printing manufacturers use the baking method to improve the printing durability of the long-lived and printed books, newspapers, etc., which is the result of removing the dirty, rubbing and baking solution, and turning on the electricity after the PS version is printed. The oven is baked. Before baking the plate, be sure to clean the dirty parts and dirty spots of the PS version with the repairing paste. Otherwise, it is difficult to remove the dirty spots after the baking. 2 The towel used for rubbing the baking plate is not clean, or the fiber on the towel is peeled off on the plate of the PS plate. 3 baking plate temperature is 200 ~ 220 ° C, baking time is generally 10 ~ 15 minutes or so, should not be too long, but also according to the temperature resistance of the PS version of the photosensitive resin film to determine the baking time . If the baked PS version of the photosensitive film is light brown, brownish red, like the ripe color of the plum, the baked version is appropriate; if the baking time is too long, the temperature is too high, the PS version of the photosensitive resin film will be baked Paste, or make the base soft.
6, before printing the plate to check whether the density of the film is appropriate, the text, lines, patterns on the sulfuric acid paper should be full of blackness, no shortage of pen breaks, large lines and wide lines of blackness should not be re-exported, can also be Bake on the electric stove to enhance the blackness. When baking, it is necessary to prevent the sulphuric acid paper from wrinkling and affect the inhalation of the printing plate. Printed large-scale books, trademarks, packaging and decoration products, whether it is a film, or sulfuric acid paper, the strokes and lines of the text should be as thick as possible, and accordingly it will be resistant to printing. Density and blackness can't meet the requirements, can't be relocated, and can be reworked to ensure the printing durability of the dried PS version.
7. The pressure of the water roller on the printing plate should not be too large. When debugging two water rollers and plate pressure, it is best not to use a good printing plate, and use the old PS plate to debug, so as not to damage the plate. At the same time, the thickness of the liner paper in the plate cylinder should be appropriate. The pressure of the water roller on the printing plate is too large, the wear and tear of the printing plate will also increase, and the printing durability will be reduced.
8. When installing the plate, check whether the liner paper on the back of the plate has wrinkles, discounts, paper scraps and small paper blocks. If these conditions are required, the lower plate should be removed and the liner paper should be leveled.
9. When printing on the plate and repairing the plate after the machine, the residual masking paste is inadvertently applied to the photosensitive resin film in the image part of the PS plate, which plays a role of reducing the film and affecting the printing of the PS plate. rate. In addition, after the upper plate is dirty, it is often wiped with a damp cloth moistened with a powder. However, do not use too much force when wiping the plate with a dampening powder. The time for wiping the test should not be too long, otherwise the photosensitive resin film of the plate will not be printed after being thinned.
10. Prevent the wear and tear of debris and layout. Also be careful not to let the plates, sheets, and other debris in the paper transport process crush the plate.
11. Strictly control the ink and water balance during the printing process. Take care to control the thickness of the ink layer to avoid spreading the ink to the blank portion of the plate. If the ink is too thick, the fine particles of the colorant, the binder and the rubber in the ink will have an increased friction on the printing plate, which will also accelerate the wear of the printing plate.
12. Use less pressure when printing. After the plate is mounted on the plate cylinder, the pressure between the plate cylinder and the blanket cylinder should not be too large. The thickness of the PS plate plus the liner should not exceed 0.65 mm, and the thickness of the blanket plus liner should not exceed 3.25 to 3.40 mm. (measured with a micrometer). Press the compaction during loading to prevent relative slippage during the operation of the offset press. In addition, accurately adjust and control the pressure between the offset roller, the water roller and the plate cylinder of the offset printing machine to avoid direct wear of the layout.