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In the process of the three uv ink overprint attention to
The education version liquid acid too would cause severe corrosion version base, low PH value. Ink drying slow; Too high will make the light type PS is part of the diazo dissolved, plate image integrity is not complete, cause ink emulsification, so that the print quality serious decline. At present, the small offset printing machine adopted by way of wetting water pile is mainly set by wetting device, under the uv ink qi da glen parker water supply unit directly wetting mechanism and kunming, according to the different ways of education version in the process of printing and the size of the control of water, no matter what kind of water supply, water is too large, appeared in print on water, easy to wash it by water, the small branch and printing paper suction expansion deformation, trouble to overprint. Too little water will obviously dirty version, but attention should be paid to prevent water ink big phenomenon. Water can be according to the size of a local area and the distribution, use paper type, the machine speed and the surrounding environment and so on. Offset printing ink balance only dynamic relative balance, there is no ideal absolute balance. Master ink balance is very important on the one hand, the printing process, the operator must always observe the effect of the printing, in order to ensure the quality of printing. Printed paper quality directly affects the speed and the quality of printed matter. First request paper should level off, cutting size should agree, paper is one of the six factors in the process of printing. And straight Angle and straightness error is small. At present, there are a lot of small and medium-sized printing factory using monochromatic offset press overprint color, simple and clear dot overprint double color, generally tended to overprint single-sided four-color, but also some positive and negative printing overprint eight colors. It asked printing machine of high quality, high precision, at the same time, also require printing operators more exquisite technology, and pay attention to in the process of overprint:
A, paper,
Wide size (width x length) error is not more than + / - 1 mm, for sheet-fed printing books and periodicals. For printing cover and a delicate picture album, wide size (width x length) error should be less than + / - 0.5 mm, and indicate the location, the rules, the smoothness of paper refers to the level of the paper surface level off is smooth, smooth degree determines the paper closely contact with rubber cloth, apparently in the same printing pressure, made of smoothness low paper printing in the printing quality of graphic clarity is poorer, for example, in the same printing conditions, use coated paper than using coated patterned paper printing effect is good; Paper moisture content between 6% and 8%, not content too high, the decrease of strength of the surface tension and appearance of paper, plastic, imprinted ink film curing slow down. Moisture content is too low, the paper prone to electrostatic phenomena, and tend to be rigid, is good for printing. Uneven water content will form a tight, falbala, curly or concave and convex inequality deformation phenomenon, folds and fault will be shown after the printing request printing workshop there is a suitable temperature and humidity, generally require temperature control at 18 ℃ to 25 ℃, relative humidity insist in 50% to 60% which is good for the storage and printing paper smoothly. In addition, the paper itself fiber type and ph value will also bring great influence to the printing.
B, printing ink
Ink can reduce its liquidity, as well as increase the viscosity of uv ink viscosity and liquidity for the printing quality plays an important role. Liquidity and viscosity of ink have a close relationship. Conversely increasing liquidity, the consistency of ink is not equal to the viscosity, the viscosity of the ink is not thick, only the same ink viscosity, consistency is liquidity. Liquidity is too small, the printing ink transfer in the process of smooth, uniform, causing the same printing surface after former shallow deep fault and other ink; Liquidity is too large, imprinted cannot accurately transfer printing, graphic layers are not clear, the ink is not full, not bright bright color, at the same time, ink liquidity is too large will cause the poles often dirty and ink. Printing process, but through the use of ink to adjust the ink viscosity and liquidity, but avoid by all means to make the print fast dry and add corn flour to ink. Can also be through the use of the fast dry ink to achieve a goal so the printing process, to adjust the ink viscosity and liquidity. Safekeeping of ink is always presses the headaches, because the ink is placed in the air a bit long, is easy to be oxidized by air and formed a thick layer of ink, next time take the printing ink, uv light oil must be scraped off the ink peel, it must be waste of ink. Presses the general measures taken is to add a certain amount of water, ink cartridges to prevent ink is exposed to air. But actually also contain oxygen in water ink oxidation, contact with the ink and water for a long time is easy to put the ink emulsification, occurs when the computer printing ink phenomenon, although to a large amount of ink, but distributing roller (mainly hard roll) is still not in the ink. Advice when ink custody, using wax paper to isolate the ink is exposed to air, or use plastic to seal, the wax paper or plastic stick in the ink layer surface, next time will be waxed paper or plastic printing the peel, but had better not use plain paper to seal, prevent when torn paper paper torn and cause trouble.
C, education version fluid
And forming a metal oxide or hydrophilic salt layer, the role of education version fluid is wetting plate blank parts. By using the principle of ink receptivity, blank set up barriers between local and ink, the ink non-stick plate blank parts. General requirements education version fluid must be weak acid medium, adjust the education version liquid PH value between 5.0 to 6.0.