Anti-staining solution for sheet leaf flipping double-sided machine
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In the 1990s, Zhang Yeping Printing Machine consisted of a single- and double-sided dual-purpose pad printing machine with a single-color, two-color variable-turning mechanism. It suddenly became the first four and the last four of 4+4. Color flip machine is available. But this does not mean that this eight-color machine is on the way, there are many ideal printers, to order such a valuable Zhangye eight-color machine, and the proportion of retreat is about 60%. In the second-hand printing market from 1996 to 2000, this eight-color machine flip machine accounted for almost half of the machine, and the number of machines was only about 20% on the market. Why are so many people unable to operate it? The main problem is that the ink on the first surface is solidified and dried, and the paper is transferred to the back, and the back of the stamp is scratched to the paper discharge frame. Even under the vacuum brake, the back of the single-sided machine is blank or The previously dried and cured ink layer print is now still uncured or only the crust print ink. Once the frictional brake is attracted, it will naturally cause scratches or scrape the ink from the previous brake. On the newly arrived printing paper, this kind of bad scratch is a double-sided machine, which is very difficult for users to accept. Therefore, the development of double-sided full-color eight-color and ten-color machines was once hindered, but today In the DRUPA 12 Dusseldorf Printing Machinery Exhibition, materials, printing presses and equipment factories have proposed some anti-stick and anti-fouling methods.
A. Anti-stick guide and anti-stick set, still used on double-sided machine, such as tangential line or binding line at the book mouth, for some pressure rollers and guides to make the paper pass, although friction, drag marks, future It can be hidden when binding, and it is more effective for book printing. Now it uses blown paper guide, so it is convenient and effective only if it is blown by compressed air without mechanical friction. As for the pressure roller surface, the pressure roller body printed on the back surface is provided with a chrome-plated rough-faced anti-sticking jacket, but the effect is not so good. Later, the ceramic rough-faced anti-staining sleeve has much better effect, but it cannot be used for a long time. Because the ink layer will always pile up, it should be kept clean from time to time, and only one point will not be stained to keep the ink for a long time. As for the vacuum brake on the paper discharge tray, it is only one of the methods to change the suction surface of the 5mm wide and small adsorption tray so that the contact surface is under a certain limit. The development of these anti-stick guides and jackets has not made much progress.
B. Using the high-speed skinning ink with fast degeneration of ink to prevent sticking, this is a place that some printing factories used to be very puzzled. It is clear that foreign countries are in the fourth and anti-four-color machines, which can be operated quickly and normally, but bought in China. The flip-type eight-color machine only found that the stains in the printing made it difficult to work. Later, I went abroad to buy the special ink for the double-sided turning machine. As a result, the effect was much better and almost finished printing on both sides. Although there was a little bit of stain, But the situation can be ignored. The original ink factory found a very fast-skinning high-shake-denatured ink. What is shaken? That is, when the ink is at rest, the polymer forms a network structure and the skin is not adhered to the ink on the watch layer. On the contrary, as long as there is shaking and sticking, the ink returns to its fluidity, and once it is shaken and adhered to stop, Under the circumstance, the ink will immediately form a mesh-like molecular structure that is ready for drying. If the pre-mixed cement is used in the plant pre-mixing tank and loaded into the cement pre-mixed car, everyone can be very clear. Knowing that the cement storage tank of the pre-mixed car must always keep rotating in a certain direction, and if everyone does not rotate the cement storage tank, everyone knows that the end will be very bad, because the cement does not move in the car for half an hour. It will gradually solidify. After three or four hours, even if it is rotated in the opposite direction, the cement will not come out again, because the cement is solidified in the concrete cylinder of the car! The printing is a double-sided special ink that uses the shaking to make the printing machine fast and crust fixed. Because it has been agitating and not skinning on the printing machine, once printed on the paper surface, a static printing film layer is formed immediately, as long as it is in front. After four or five colors are printed, more than one second of paper feeding through the middle three transfer rollers is enough to produce a relatively non-stick crust (drying) phenomenon, meaning that the ink is not completely Drying through the bottom, but the ink level on the surface, when touched with a finger, it does not penetrate the wet ink to produce fingerprints and the ink adheres to the fingerprint surface. This is called the quick-skinning surface of the dry, matching the ceramic rough surface on the back pressure roller. Anti-sticking clip, under the four-color embossing of the back printing, as if walking through the water, it will not produce sticky ink marks, and because it does not pull up a few sheets of printing paper wet ink, sticky Do not print the printed surface of the post-printed sheet to produce stains. In addition to the anti-stick jacket, the high-waist ink also occupies an important anti-sticking role, but the four-color ink of a foreign one-kilogram double-faced flip machine costs 1,500 Taiwan dollars, which is almost impossible for many printers. Therefore, there will be some use of some fast-skinning ink to do double-sided turning machine printing, the effect is not so ideal, barely make do with it, so in foreign successful cases, it is long used to use high-shaken densification ink to promote early crust as the main method.
C. Forced curing using a hybrid Hybrid ink. If you are using a UV-curable ink for each color of the front-printing machine, and each printing unit has a UV lamp, then it is the most ideal flip-top printing, the ink that has been completely dried on the printing surface, afterwards Paper transfer, embossing, and even delivery of the printed surface will not be sticky, dirty or scratched. However, the use of four UV lamps has its power consumption. Therefore, some ink factories in Japan cooperate with the printing machine manufacturer to use a hybrid Hybrid ink, which can be printed without using a special rubber ink roller or blanket. Ink, when the four colors are printed, when the printing roller is turned out in the center, the printing ink of the mixed ink is cured by a set of UV lamps, so that the back printing is not contaminated, if The same type of ink and curing method are also used in the four colors of the post-printing, so that there is no back printing or sticking on the delivery table. Why not use UV ink to use Hybrid ink, there are two reasons, UV ink is 5-6 times more expensive than general ink, Hybrid ink is only 50% more expensive than ordinary ink in Japan, the cost is low, the second is the printing plate of Hybrid ink, ink Rollers and blankets can be used as long as they use a general ink system, while UV inks must use UV-resistant printing plates and rubber rollers and rubber clips. However, Hybird ink produces real-time curing when the printing-to-curing time is not lengthened. The surface is rough and dull, that is, when the yellow ink is printed on the first side, it immediately enters the UV light to cure, and the ink leaves the blanket surface. When the drawing effect is performed, the surface of the surface such as maltose is uneven. If the surface is "falling" for 5-6 seconds, the surface is smooth and smooth, but after the fourth color is pressed, the roller is cured to a speed of 12,000 sheets per hour. 200 minutes, then only 0.6~0.7 seconds will be irradiated and cured immediately, and there is not enough ink to reduce the gloss time, which is quite helpless. Therefore, Hybrid ink is effective in drying, in the middle and in the back to prevent sticking and staining, but it is also a printing method with a matte finish.
D. Using low-radiation energy UV LED, H UV or LE UV lamps, single-sided curing and then flipping into the second side of printing, this way and printing with UV lamps, using Hybrid ink for double-sided printing, are The same curing side enters the back side printing, and after the back side printing, it also performs a mandatory radiation chemical curing. The only difference is that the general UV lamp is used in general UV ink or Hybrid ink is high power UV lamp, if eight The color machine uses 80Kw of kinetic energy, then the UV lamp used in the double-sided machine must use 100Kw of lamp power consumption. The main reason is that the effective UV light generated by the UV lamp is only 28~30%, and the others are visible light that is ineffective for UV ink curing. Or a larger part is that IR IR, which we don't want, accounts for 51% of the ratio, which is very troublesome, because IR not only raises the surface temperature of the printed object by 15?~25?C, but also makes printing. The machine and the surroundings are very hot, so it takes a lot of cooling energy to take away the IR infrared heat generated by the lamp, so the UV curing ink can use the UV chemical energy to make the UV ink in less than one second. machine Start-up, and make the UV oil photo-sensitive monomer to polymer link curing, this effect does not require the heat of infrared light to act, but the infrared heat energy also has a mechanism to increase the temperature and increase the chemical efficiency, but the impact is more weak. The new generation of high-spectrum ultraviolet light source is called H-UV by UV LED or Komori press, and LE (Low Energy) used by Heidelberg. Many people think that UV LED or H UV and LE UV are a relatively powerful new light source energy. In fact, the opposite is true. It only moves the spectrum of UV light to the near ultraviolet light, and the UV B of the larger chemical energy. UV C does not occur or decrease occurs. Like UV LEDs, crystal light emission occurs at a single spectral frequency. From different spectrums such as 365nm, 375nm and 385nm, only one spectrum of light is emitted. Therefore, the UV LED itself emits less light and heat, and does not need water to cool the air. It is enough. To use water to cool, it only needs a small cooling capacity. However, if the UV spectrum is used to cure the ink object, if the photosensitive spectrum is too concentrated in the near-400nm violet portion, the ink itself is too low in sensitivity spectrum, and it will not cure at all. That is, if you use general UV ink printing, and use UV LED light source to cure, it will not have a curing effect. Strengthening the ten times of the light sensitivity is still not enough to cure, because the ink is too sensitive to high frequency 365~385nm, so The UV LED ink is not only sensitive, but the sensation spectrum must be matched to the high spectrum of the UV LED, just like a lock should have a proper key to play it, otherwise it may not be effective. UV LED has a good chance to use the color 4+4 double-sided turning machine instead of the highly shaken double-sided machine ink, and it is clean and neat, and there is no trace of ozone. It is ideal. UV LED has a long-lasting working life of 15,000 to 20,000 hours. Unlike ordinary UV lamps, or high-voltage electric gas-conducting lamps with H UV and LE UV lamps, it has a life of 1,000 to 1,500 hours and must be lit up. In order to respond to the printing with the boot. H UV cuts off UV C below 290nm, and there is still a small part of UV C below 320nm, mainly occurs in the near-ultraviolet light spectrum of UV A 360~400nm, so it should be similar to LE UV, and H UV ink The sensitized spectrum does not need to be concentrated like UV LEDs, it can be in the range of 360~400nm, and some IR occurs in H UV lamps. It needs water cooling and air cooling devices, so many printing machine manufacturers in the world such as Ryobi Mitsubishi Heavy Industries, focusing on UV LED curing, KBA seems to be interested in keeping up, because the energy consumption of UV LED is only 20~25% of the energy of ordinary UV lamps, which saves energy and reduces the occurrence of carbon footprint without ozone. The UV LED's illumination and cooling devices are very compact, and there is almost no light leakage from the human eye. The H UV energy consumption is 30% of the general UV lamp. It is not necessary to spray powder on the paper receiving table of the printing machine, that is, it can be processed by origami, which is very beneficial to the improvement of the printing process. Moreover, regardless of the printing of UV LED, H UV, LE UV, the temperature of the paper surface does not rise at all or only rises slightly, so in addition to the problem of roughening of the printed surface which is cured by printing, the energy-saving UV lamp must also be cured. Appropriate optically active inks can work.
E. Water-based glazing double-sided turning machine ink curing method, which was developed this year at DRUPA 12 KBA exhibition, that is, high-speed flip printing machine, if the ink must be cured by UV or UV LED light, Then the printing speed will become a key factor. Generally, the printing speed below 10,000 sheets per hour may be OK. To 12,000 sheets per hour, it depends on the thickness of the printing ink, the ink layer is too thick, the reflectivity is too high, or the penetration is insufficient. Ink layer, maybe it can't be completely cured, so it can't pass the high-speed flip printing of more than 15,000 per hour at high speed, but KBA's R106 double-sided turning machine has 20,000 sheets per hour, which is equal to 30 years. The speed of the front-end lithographic printing press, while the double-sided flipping speed of the printing speed still has 18,000 sheets per hour. Obviously, the combination of the original UV or low-energy UV light high-sensitivity ink cannot meet this demand, even using the height shake. The wet printing method of denatured crust and anti-sticking is also facing an unsolvable problem. KBA engineers use the technology of water-based glazing to combine the wet ink layer of the color printing surface with the water-based glazing technology to combine the wet ink layer of the color printing surface with the aqueous acrylic coating material. The printing ink layer seals the deadlock under the water-based acrylic coating layer, on the one hand, it can add brightness and increase the added value of printing, and can also make the matte surface light, resulting in a more elegant coated surface, and the glazing The coating is naturally outside the 4-color unit, and there is a cavity-type water-based glazing unit before and after the addition, then the eight-color machine becomes a 10-color machine. However, the first printing surface should have sufficient IR and hot air effect after glazing, in order to achieve sufficient curing effect of the water-based glazing coating layer under high-speed printing, so the KBA engineers printed and printed on the front five and the last five seats. Between the light units, two units are added. When the transfer roller is turned onto the printing surface, the IR heating air is used to evaporate the water of the water-based glazing paint, and the surface of the printing surface is cured without sticking. Coating material, which is very safe for back-color printing and glazing, without staining and soiling. It is very effective and cost-effective anti-stick curing, including the problem of attracting drag on the paper tray. Solved, and can be adapted to the world's highest speed double-sided turning machine. Like KBA's R-145 double chrysanthemum full-turning machine, the direct printing speed is 17,000 sheets per hour, flipping 15,000 sheets. If the surface speed of the printing cylinder is 45% faster than the R106, the general UV light irradiation can no longer be used. It is useful for water glazing anti-staining.
In the color double-sided printing method developed by 20%, through the synchronization of each plate cylinder, can make a shorter version of the response, and the double-turn color one-step printing long flip machine, and gradually step out of their own market positioning. And the general single-sided four-color machine is not only sticky and anti-printing, it can be printed on the back after drying, and the printing effect is reduced due to uneven powdering and paper, which will make mistakes and increase production time and space. There is almost no profit and more complete conditions for the eight-color long-turning machine, and it also clarifies the new positioning of a cultural and commercial double-sided color printing.